Prior to 1980, Colt was contracted to make 1,000 Series 70 MKIV's (1911-type) in 9mm Steyr caliber for an Italian firearms distributor. Italian laws preclude current military calibers from being sold to the public. There are a number of surplus Steyr-Hahn pistols in Italy due to the pistols captured during WWI and due to the war reparations of weapons from Austria. Note that Fiocci is the only ammunition maker who makes 9mm Steyr ammo on an ongoing basis.
Colt made about 100 extra MKIV's to serve as warranty replacements for the 9mm Steyr pistols. After a period of time, these unused warranty pistols were sold new-in-box in the USA. The magazines as well as the pistols are stamped 9mm Steyr in the usual places.
A 38 Super magazine seems to work quite well in these pistols if you choose to shoot it and want an extra magazine.