When the police are chasing Tony Van Dyne and his gang the scenes where Tony is shooting at the police show the internal car scenes for Tony's car as having rounded rear and side windows. The exterior chase scenes show Tony's car as having square rear and side windows. This is probably because this film used recycled action footage from the film 'Public Enemy's Wife (1936) , of which Bullets for O'Hara is a remake.
When Tony Van Dyne has his host, McKay Standish, open the safe he and McKay struggle causing the bonds McKay Standish is holding to go flying all over the room. In the next scene they are not there.
Patricia and Tony are riding in the back of a car after he robs the Standish's. The rear projection out the back window of the car shakes violently at one point - as if the car went over railroad tracks - but the pair doesn't move at all when this occurs.
During the car chase and shoot-out, they pass a sign that reads "Palm Beach 87 miles". The chase then goes through terrain with very large hills, whereas south Florida is pretty flat.