Visible crew/equipment: As Eddy stands up to go out of Enrico's restaurant with Bullitt, look at the only window that is in the shot. A short male with black hair gets past the crowd-control policeman (in a white helmet) on the sidewalk. The cop reaches out to stop him, but it is too late. The walkie-talkie in the cop's hand has a long antenna. It's quick, subtle and quite humourous.
Visible crew/equipment: During the chase scene, it is too obvious when the hitman in the Charger is replaced by a dummy. Most of the time, such as when the hitmen lose Bullitt, just before the chase begins, we see the hitman with his right shoulder leaning on the passenger door. When we can see into the Charger, either the actor is leaning against the door or we see the dummy sitting about a third of the way away from the door, too much towards the centre of the car. The dummy doesn't flop well with the motion of the car, either.
Visible crew/equipment: When Bullitt gets out of the cab at the car wash, just before the big chase sequence, the cameraman's reflection is visible on the door window. (01:02:15)
Visible crew/equipment: When Bullitt is in the restaurant, you can see a crew member telling people to get away from the filming.
Answer: Notice: Aprea is credited as "Killer", not "The Killer." I think this confuses reviewers, as they assume he must be one of the hit men. However, the hit men are credited as "Phil" (Bill Hickman) and "Mike" (Paul Genge). Genge is much older than Aprea and Aprea does not look like the grey-haired hit man, as another contributor has pointed out already. There is no other killer in the plot. Perhaps Aprea's scenes were cut.