The sight is similar to the Novak dovetail competition sight
https://www.novaksights.com/Detail.a...00514&CAT=9544
In the 97 handguns book there is a picture of a "mid generation delta pistol" that has the Novak sight. the article was written by Ken Hackathorn so I'm assuming it's accurate. I have over the years saw pictures of purported Army pistols sporting the Wilson (model 61 I think) sight and a few years back Vickers put up a picture of a clone he made of his first "unit" issued 1911. That had the shorter version of that sight. Kind of a nod to the originals but not a clone.
I wish Wilson would drop the scallop around the sight notch. I have a set on a Glock and find it distracting would also prefer a square notch like the Pepperoni sight Wilson makes for the Berettas.