a Swensight uses the original Colt dovetail but moves the rear blade to behind the top of the slide, and provides a BoMar sight picture... as commented, easy to cut the front for a dovetail... Swensight may be available on the new old stock market... Maryland Gun Works makes a similar sight, but not as classy looking as the one by Swenson
https://www.bing.com/images/search?q=maryland+gun+works+rear+sights&qpvt=maryland+gun+works+rear+sights&FORM=IGRE