Uh, just to be annoyingly picky, the Ballester Molina isn't exactly a 1911.
http://www.sightm1911.com/1911%20History.htm
There are Argentine 1911's, some made by Colt and some made by Argentina. Those are 1911A1's, and all 1911 parts interchange. They usually have DGFM or FMAP marked on the slide.
Argentina also made a less expensive to manufacture pistol called the Ballester Molina, that looks like a 1911 without a grip safety. While it looks like a 1911, it iisn't quite, and not all parts interchange.