Bowfinger takes off his fake pony tail and puts it in his left coat pocket before going into the restaurant. When he pulls out his business card and gives it to Jerry Renfro, he puts his hand in his right pocket, and the fake pony tail is attached to his card.
When the 2 cops pull over Kit's Mercedes, the driver exits and draws his weapon, then from another angle he's back behind the wheel, only to return to have his weapon drawn again a couple seconds later.
When Afrim and the LA Cop pull Kit over at the end of the movie, the LA Cop gets out of the car first. When Afrim is getting out, the LA Cop is sitting in the car talking on the radio.
When Bowfinger is in the bedroom with Daisy, counting his money, the picture behind the bed changes angle between shots (the first part of the scene was re-shot months after principal photography had finished, to include a shot of the table set for two).
When Bowfinger is sitting on the bed counting his money before Daisy enters (appx 53:00 to 53:10), there is a dollar bill stuck to the back wall of the money box. When the camera cuts to the door and then cuts back, the dollar is gone.
The license plate on Kit's limo reads 'MIND HEAD'. California plates only have 7 characters.
When reviewing a script with his agent at the beginning of the movie, Kit says that the letter K appears 1,456 times in the script, which is perfectly divisible by 3, meaning that KKK appears 486 times. 1,456 is not exactly divisible by 3. 1,458, however, is, and gives the stated division result of 486. This could be an intentional error to jokingly suggest that Kit has poor math skills.
When Kit cannot be found, Bowfinger decides to take on a double to fill in. Although he says that they'll shoot him from the rear so it won't be obvious it isn't Kit, the first scene involves Jiff running across a highway, directly towards the camera. This is because Jiff looked so much like Kit, he could get away with filming his face. Also, Bowfinger said he'd shoot the double in wide shots (when the actor is far away from the camera). So they could have simply cut the shot when Jiff got too close to the camera.
In the security room at the observatory, the monitors are showing nominally live action. However, videotape dropout artifacts are present on the screen.
When Kit shoots the cymbals, the blasting caps are visible both before and after.
A "bounce card" (light reflecting screen) is reflected in the window of Kit's car.
At the observatory, Kit and the actress are running down some stairs. On a monitor in the security room filming that same staircase, a boom mic from the main film unit is clearly visible.
When Bowfinger leaves Carol, who is in makeup across the street from the coffee shop, here is a woman who is walking down the street away from them. She stops, looks over her shoulder at Bowfinger and then realizes he's moving and starts walking again.