"Differences",not all shown; front sight(but they can vary as some pre wars had "special orders"),ejector rod tips or knobs, single screw in right side to retain the crane, checkered cylinder release on pre wars, plain on post wars,checkered hammers/triggers,versus grooved on most post wars,wood stocks that reappeared on the post wars(after the "Coltwood" era,circa 1953),were cheaply checkered(IMO) and had different medallions,and blued screw/escutcheons. And of course roll marks and serial numbers!
All subtle differences,that demonstrate the effort to cut labor costs by Colt,but S&W did the same,"up the Connecticut River Valley"!
Passed on another Mark III Official Police yesterday.As new,no box, for $300-350. Just couldn't make my earlier,1932-1959, battery of O.P.'s share their part of the gun vault with the decline in quality. Been trying to conquer my antipathy to the Mk.IIIs and Mk.Vs,but after a couple of "bad ones",I just don't like their feel,fit or finish.