When the Econo Guy leaves the motel to go to Abby's Pizza, he's only wearing his black long sleeve. When he's at Abby's Pizza and flips it off, he is clearly wearing his plaid shirt from earlier in the movie.
M.D. Schneider and the tripod for the camera can be seen in the mirror after the Econo Guy gets out of the bathtub to go outside for a cigarette.