The Girl on the Balance Beam - S5-E18
Other mistake: Twice during this episode, when they're dispatched to a "woman trapped on a wire" and also to the "train fire", we see Engine 51 heading out with two firemen standing at the back of the engine, and they are Johnny and Roy. This footage is actually from the episode "The Old Engine" in season 3, when they got the new Ward La France engine for Station 51, and since Roy and Johnny were waiting for the previous shift to return with the squad, Captain Stanley told them to jump on the back and go with them on their first run with the new engine.
Continuity mistake: When Roy and Johnny are in the backyard with the couple and the mother-in-law, after Johnny gets off the phone with Brackett, he has the black notebook in his left hand, but in the side shot it's in his right hand, then it returns to Johnny's left hand.
Visible crew/equipment: At the station, when Johnny and Roy talk about The Stewardess and then while Chet is mopping the floor, the bulging outline of the mic transmitter is visible on the front, left side of Roy's shirt, above his belt.
Visible crew/equipment: After Roy is electrocuted and falls from the second floor window, when Karen runs over to him and starts CPR, the bulging outline of the mic transmitter is visible on the back of Karen's white uniform.
Visible crew/equipment: After Karen, the new trainee, goes to the waiting room to speak to the elderly patient's wife, when Dixie walks over to Roy and Johnny to ask how she's doing, the outlines of the mic transmitter and wire are visible on the back of Dixie's white uniform.
Visible crew/equipment: In the ambulance, when Roy administers the bicarb and then the isoproterenol IV, the outline of the mic transmitter is visible on the left side of the third paramedic's shirt, as he's doing chest compressions.
Continuity mistake: During Johnny and Roy's flight to LAX there are a few shots of the airplane in mid-air and when it lands, and the type of airplane changes - note the engines and tail.
Visible crew/equipment: At the start, when Johnny is telling The Stewardess about the underwater rescue and in following shots, the outline of the lavalier mic wire and the dark strap (that holds the transmitter) around Johnny's waist are visible on the back of his shirt, and the mic transmitter is visible on the front, left side of his shirt, above his belt.
Visible crew/equipment: After the airplane rescue, at Rampart when Brackett congratulates Roy and Johnny on a job well done, the outline of the mic transmitter is visible on the front, left side of Roy's shirt, just above his belt.
Continuity mistake: When Squad 51 heads out on the first call, Roy pushes the tool cart up against the wall map and the rear apparatus bay door is down, but in the next wide shot as they head down the driveway, the tool cart is gone and the rear door is raised all the way up.
Continuity mistake: During Roy and Johnny's rescue of the sky diver, the stuntmen are not wearing the fire department uniform shoes, they are wearing different shoes, and Roy's watch differs as well.
Involvement - S5-E19
Revealing mistake: The former head nurse is supposed to be unconscious when she's picked up from the couch. Yet she puts her hand up on a shoulder when being carried out.
Other mistake: When Early and Morton are examining Johnny, Early tells the nurse, "Type and cross" (the blood vials she's holding), but the weird subtitles read, "Cut and cross." Subtitles from Universal Studios 2010 DVD.
Visible crew/equipment: When Squad 51 is dispatched to the car on top of a roof, it cuts to John and Roy driving in the squad as John responds to dispatch, and the reflection of the filming vehicle is visible on the squad's surface.
Continuity mistake: When dispatch drops the tones at night, waking all the guys up, notice that Marco's mustache has vanished, though it reappears later. Additionally, they all get into their boots, turnout trousers, only white T-shirts, suspenders, and grab their dark jackets, but when the bay door opens they're dressed in their uniforms as they respond. Then at the fire they're in the turnout trousers, and Johnny and Roy are wearing the uniform shirts when working on the burn victim.
Visible crew/equipment: When Roy leans over Captain Stanley after he was electrocuted, the outline of Roy's mic transmitter is visible on the back of his shirt.
The Tycoons - S5-E23
Character mistake: Chet states that he stops for breakfast at the hot dog stand. When Roy and John are eating there, a sign in the background says it opens at 11:00.
Continuity mistake: After Roy gets his leg bandaged at Rampart, as he and Johnny exit to their truck, they suddenly get haircuts. Looks like a shot from an earlier season.
Continuity mistake: When Roy and Johnny go to get on the helicopter they are with only the orange bio-phone, but after The Boat brings them back to the shore you see them running to the helicopter with the patients, and they pick up their large black trauma box. They didn't have it with them when they left.
Continuity mistake: When transporting the heart attack victim from the plane the ambulance starts as a Ford and ends as a Chevy.
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 ★