I'll talk to the other Arm Affair owners. Seems like a no brainier.
Can we carry guns in the parade?
Definitely yes, at least until you are tackled to the ground by local law enforcement and led away in handcuffs. So, you should probably bring a T-53 so you aren't worried about getting it scratched up.
Weapon of Choice: Illudium Q-36 Explosive Space Modulator bolted to a crappy old T53 stock