Other mistake: The vigilante bike-cop slaps a supressor on his Colt Python. A suppressor on a revolver doesn't work without serious modification. There's only one revolver I know of which would be able to use a suppressor, namely the Russian Nagant M1895. And that's due to the gas-seal system in the cylinder, which seals all the out-gassing, only letting the gases out the muzzle-opening. (01:01:00 - 01:10:00)
Other mistake: In the final credits, DiGiorgio is misspelled as "DiGorgio."
Other mistake: In the scene where the mob boss gets interviewed in the garden atrium after being freed, the news media pushes up to get really close to the podium. Note that the first reporter, dressed like Gilligan, trips and almost falls into the podium. He catches himself but has to keep his head down during the rest of the shot.
Other mistake: In the beginning credits Harry says "This is the 44 magnum, the most powerful hand gun in the world" but later when he's at the range with David Soul and the other cops, when asked about his what his gun loads he says he uses .357 lite magnum.