Saigon, I found a Colt (9mm) like yours but in 9mm steyr. Ever heard of that? Colt made some on a contract for a European LE agency.
They are quite uncommon especially in the USA, it would make a neat collector item but ammo would be a pain to acquire for a shooter. Intended for the Euro market where some countries did not/do not allow military calibers for civilians. Factory chamberings for 1911 patterns from Colt have been strange and varied sometimes.
I have only seen one of these guns in person.