OK, I've noticed this twice, both times have been from screen caps/pics from GB2. Look at the screen cap of the equipment on the table in the courtroom; take notice of the particle thrower on the pack you can see the best. Now goto the pic preview section of GBProps.com and look at the full display pic from Planet Hollywood; again look at the particle thrower. Both the barrels look bent. In the courtroom it looks bent out, and in the PH display it looks a bent inwards. I realize that on the hero pack the barrels can twist, but that would not explain why it's bent. And the courtroom pic it is REALLY bent. Here's the pics I'm referencing:
http://thegrid.topcities.com/classicgrid/equipmentcr.jpg and http://www.gbprops.com/preview/10.jpg. Keep in mind the display one doesn't seem to be bent as much, but this is puzzling me. I wonder if it's the same prop in both pics and just got bent by accident.

You know, I noticed that too about the court room. I also noticed in the first movie that when they go to the hotel and are walking up to the elevator that Ray's bumper is bent upwards and Pete and Egon's are not.

What probably happened is that the barrel of the gun previously broke during filming and since it was just going to sit on the courtroom table and not be worn, it was temporarily fixed just for the shot. At some point afterwards it was probably repaired again and what you see in the PH pic is the final result of the repair. If this is indeed the same pack, then nice job eagle eyes!