The MKIV Series 70 Government Model Colt pistols were manufactured from 1970 to 1983 and have "70G" as a prefix in the serial numbers on the models made from 1970 to 1976. The models made from 1976 to 1980 have "G70" suffixes. Models made from 1979-1981 have "B70" suffixes and models made from 1981 to 1983 have "70B" prefixes. The Series 70 had, in addition to the Government model, a Series 70 Combat Commander, Series 70 Lightweight Commander, and Series 70 Combat Government. The Series 70 featured an accurizer barrel bushing for improved accuracy.
abw, I have to disagree that there were ever Series 70 Commanders or Combat Commanders. (The error-filled Blue Book makes this error too.) The short barrel guns never had the collett bushing that is the characteristic of the Mark IV/Series 70 guns, and were never marked "Mark IV/Series 70" (or is it Series 70/Mark IV?).
There were some GOVERNMENT MODEL MKIV / Model 01970 that had serial numbers with the SM prefix that was found on Service Model Aces. Many year ago I saw one in a shop. First thought was that it was mixed up parts from somebody who owned both a Government Model and a Service Model Ace.
Dealer had the box with label details matching the pistol.
Caliber: Colt .45 A.C.P.
Barrel Length: 5"
GVT. MODEL MKIV / Model 01970 S/N SM36xxx
Probably made in 1981, based on Larry Hackers list of serial numbers.
No idea how many Government Models were stamped with the SM prefix. I have never seen another one!
Has anybody in the group seen or heard about any of these??