Well, according to the Gun Wiki, the FBI used them until 1976.
http://www.youtube.com/watch?v=HYTUc...eature=related
This guys, who looks credible, says 1974. Further more, he says military stocks, so it very well good have been a -1928A1.
As far as the Super .38, he's stateside, ammo supply wouldn't be that big of an issue.