It ends up Anchor Harvey makes them, no DPMS markings of any kind and reviews are generally good- so I ordered one off the link and then an A1 rear sight assembly off Midway. After I put it together I’ll post an update.
Also, you will need a port door assembly, CAR 6-hole handguards, and a CAR fiberlite stock as well. That should be about it. Model 1 Sales has fiberlite stocks. They are not Colt, but they work well. Colt fiberlite stocks can be found , but they will be a little pricey.