Visible crew/equipment: When squad 51 parks upon arrival at the gas station the array lighting is visible on the driver's door.
Other mistake: When Station 51 is dispatched to the "freeway accident," as the engine and squad roll out of the apparatus bay, we can see the real 127's vehicle still parked in the bay, near the rear door.
Visible crew/equipment: When Station 51 is on scene at the freeway accident, after the two girls are rescued from the wreck, when the explosion occurs Roy and John dive to the ground, and as the camera zooms out we can see the top of the location's array lighting unit, just past the engine's hose bed at the bottom left corner.
Continuity mistake: At the gas station, when Captain Stanley asks Marco to open the gas pump and close the shut-off valve, Marco is wearing two rings - one on each of his ring fingers, but when he is nearly electrocuted both rings have vanished.
Visible crew/equipment: When Chet is trying unsuccessfully to get Henry to use the dog house, the outline of the mic transmitter is visible on Chet's back.
Revealing mistake: At the gas station, when the pump sparks and catches fire, we can see that it's not gasoline on the ground with the water from the fire hose, but instead it's floating thick gobs of stunt fire gel with burning flames.
Visible crew/equipment: When the guys are at the gas station with the broken pump nozzle, after Marco and the stretcher are loaded onto the ambulance, the reflection of the location array lighting can be seen on the back of the ambulance, when Johnny shuts its doors.
Other mistake: While Charlie is trying to figure out what's wrong with the squad, when Captain Stanley, Roy and John are sitting around the table, there's a can of scouring cleanser which has yellow tape covering the "a" and "x" so all we see is the "ja" on the can, in order to hide its brand name, which is Ajax.
Visible crew/equipment: When Charlie's at the station, complaining that every time one of the squads breaks down it's only crying out for mercy against the drivers, and that firemen are the worst thing to happen to the squads, we can see the reflection of the boom mic on the windshield of Squad 51.
Continuity mistake: While Charlie is finishing up on the squad's engine, Captain Stanley hands Johnny the address in the canyon that has overgrown weeds, and when Johnny packs up the toolbox, Charlie holds out the roll of electrical tape and the combination wrench, with its open-end up. However, in the next shot the only thing Charlie holds out is the wrench, but with its box-end up.
Visible crew/equipment: After rescuing the injured worker from the top of the sky-tower at Oceanland Park, when Mike has a problem starting 51's engine, we see reflections of array lighting on the squad's surface. And when Captain Stanley moans that he'll have to call Charlie, he stands in front of the engine and calls out, "Why me?" and one of the location's array lighting units is visible at the left side.
Audio problem: When the guys reach the top of the tower ride at Oceanland Park, we hear Captain Stanley say, "Kelly, you go up on top and throw the tag line over the side, we'll take the stokes up that way," but Cap's mouth is saying something entirely different.
Visible crew/equipment: After Johnny and Roy are called back into the home of the young couple, who were issued the fire-code violation ticket, when Roy is on the Biophone with Rampart, the bulging outline of the mic transmitter is visible at the left side of Roy's shirt, just over his belt.
Visible crew/equipment: When the guys are on the tower ride during the rescue, the shadow of the chopper (and its rotating rotor blades) doing the aerial filming becomes visible, when the ride reaches the bottom. Then the shadow of the entire chopper moves in directly in front of the ambulance, as they load the ambulance.
Continuity mistake: When Roy and Johnny get to the address in the canyon that has overgrown weeds and shrubs, in violation of county ordinance, Johnny is empty-handed when they knock on the front door, but when they're told to come in Johnny is now holding the large fire-code violation ticket booklet.
Continuity mistake: After Station 51 is dispatched to Oceanland Park, when the engine and squad drive through the parking lot and pull up in front of the sky-tower, the entire left side of the lot is completely empty, but in the overhead shot as they head to the top of the sky-tower for the rescue, that side of the lot is filled with buses, cars, and other vehicles.
Continuity mistake: When Station 51 is dispatched to Oceanland Park, when the engine and squad arrive on scene at the sky-tower, Engine 51's hosebed is suddenly entirely covered with green canvas.
Visible crew/equipment: When Squad 51 stalls and the guys call for assistance, when Charlie shows up and walks over to the squad, the reflection of the camera rig tracking backward can be seen in the squad's vent window. The reflection of location set lighting is also visible on the spotlight and squad.
Continuity mistake: When Charlie notices the scrapes on Squad 51's tire and complains that its drivers are messing with the squad's alignment, note that the scrapes' positions change twice, which means that the tire has rotated, even though the squad has not moved since the start of the scene when Chet walked over.
Continuity mistake: After Charlie checks the squad's engine, and replaces the adhesive bandage on the wire with proper tape, Charlie places the tape roll back into the tool box, but when John collects the rest of the tools lying around, Charlie gives him the role of tape, which is out again.
Answer: I was rewatching a few first season episodes of Charlie's Angels (1976), and in S1xE6 "The Killing Kind," I recognized the same actor. So, to finally fully answer your question, the two baseball players in School Days are played by Rod Perry and Sean Fallon Walsh.
Super Grover ★