Howdy
I was under the impression that the speculation is the iron frames themselves may have been made by Colt, but the guns were still assembled by the New Haven Arms Company. The way I heard it, the equipment to forge and produce the frames may not have been installed in the New Haven Arms Company's new factory yet, so Winchester contracted with Colt for the frames. But I believe he had the capacity to assemble the rifles in New Haven. That's the way I heard it anyway.
Stepenmud:
If you are referring to the blunter provile at the top of the butt plate on the original iron framed Henry, Uberti has copied that particular detail on their current steel framed Henrys.
Here is a photo Happy Trails sent me of the stock of my Steel framed Henry, compared to one of the many stock brass framed Henrys that flows through his shop:
P.S. Notice the similarity of the shape of the lever loop too. No tab at the end of the loop bearing against the frame on either the original iron frame, or my steel frame. Let's not talk about the case hardened colors.