After Burnat shoots the speaker, a "bullet hole" can be seen in the upper-left of the speaker, but then the speaker tips over and the "bullet hole" falls off.
When Bob Burnat/Bobby Boogie locks Del Murdock in the bathroom, Bobby pulls the door shut, inserts and turns the key, then pulls the door shut again. The door was still cracked open while locking it.
After Bob "Bobby Boogie" Burnat fires the Colt .45 and shoots the speaker, he holds up the gun for Johnny Fever to take. When he does, you can see that the hammer is in the down (uncocked) position. When the Colt model 1911 is fired, the slide moves to the rear to eject the spent case and to load a new cartridge. This action leaves the hammer in the cocked position ready to fall on the freshly chambered round. The hammer being down indicates that the gun was never fired.