The first of the Avenger-style holsters came out of the Bianchi stable in 1977 or so, and was followed by a host of copies (at least one of which, Sparks, claimed to have been first with theirs -- ten years later). Here's a partial 'list' in pics, in sequence. They're all marked. Not shown is one I did for Assault Systems in a hybrid fabric/synthetic leather.
20180530_102517.jpg
20180530_102551.jpg
Note that only the last one, which is an extreme sophistication of the original Avenger, is the only one with a slide guard -- which was also invented in the '70s (I believe by Gordon Davis). There is a HP there, and a Glock, but the rest are all 1911s.
20180530_102631.jpg the earliest
20180530_102645.jpg the latest
All Avengers except mine are very simple beasts consisting of two leather pieces: the body, and something for the belt. Mine are made from 7 leather pieces plus the hardware -- that's called progress.