Continuity mistake: When Mr. Garrison is carrying around his gun, it is not the wood finished gun with the wood colored hand grip that he bought, it was the other one that had the grey hand grip. (00:14:20)
Suggested correction: He says he will have it (wood finish) then it shows him walking through town. Plenty of time for him to change his mind again.
Perhaps, but later when Stan and Wendy interrupt him, his gun exhibits wood furniture again. Unless he purchased both, some error has been made here.