Other mistake: Sam tells Rob "Laura could be late because of the rain". Yet neither Sam, Laura, Millie or Clark had any wet clothes, jackets, hats etc. Rob was the only one that had gotten soaking wet. Also when looking into the window he taps on the glass with a white glove (which he didn't have on when he got into her house).
Other mistake: Right at the beginning of this episode Rob says "9 years ago right in this office... I just came on as head writer 2 months was all... Buddy, Sally and I were sitting at this desk, writing a sketch, and you (Mel) came in with some special news." (so on and so forth with that line.) Rob, Sally and Buddy weren't in "this office" building... Didn't even have the same desk or furniture.
Other mistake: Evan from the insurance company comes over to ask Laura and Rob several questions but not once does he find out any names from the party. But the next day Buddy, Sally, Mel, Jerry and Millie all get really angry because of Rob and his interrogator just assuming that they stole the watch.
Other mistake: That mirror behind Rob at the hotel in their room has fog (condensation) on it which means that the humidity there in "Mexico" is really really high or it's over 100°F in their room with humidity or unless it was raining inside their room, the window behind the bed is perfectly clear. (Real life that mirror would not be all foggy.) Also Rob, Laura and the hotel guy would have been sweating up a storm if it was really really hot out there. Which it wasn't. (00:13:52)
Other mistake: Laura tells Rob that Jerry is fixing the fence. Then all of a sudden this banging that sounds like an iron hammer and chisel on cement starts up. If Jerry was actually fixing the fence it would have been the whole time, right when Rib got into the kitchen, not right after Laura told Rob that Jerry was working on the fence.