A Fistful of Paintballs - S2-E23
Corrected entry: When the group arrives at Fort Hawthorne, Starburns tells them they need to give up their weapons, and Troy dumps his in the box. Then, Pierce tells Jeff that only "Hawthorne personnel" can carry weapons inside. Troy was a deputy, so he shouldn't have given his guns up (Starburns should also likely have said something to this). Troy may act silly sometimes, but there wasn't any bit here, so it's inconsistent with his character.
Correction: While he may have been working for Pierce, it is still highly unlikely he would let any member of the study group carry a weapon inside Fort Hawthorne. He was still angry at them for excluding him and wanted revenge.