I'm not sure I'd want to change it from factory specs without reason. I understand cosmetic changes to make a more faithful copy of the original, but this is too close to the boiler room for me to contemplate the rebate you propose.
Colt had a gap in their model lineup. The 1849 was popular for "concealed carry. The 1851 was a popular belt pistol. The Dragoon was way too heavy for even a horse pistol. A new belt pistol in the dragoon caliber was desired, and possible with more modern steels. Colt made one prototype in the new configuration. Then, the lights went on!
With an 1851 frame made of modern steel, a barrel group in .44 could be made to fit without manufacturing a new frame size. As the new cylinder had to be wider for .44 caliber, a "shoehorn solution" was tried. Step down the rear so the existing lockwork could be made to operate, with a wider mouth for army size bullets. By golly, it worked. Add in the creeping rammer being worked on for the navy/ranger, and a classic was born.
I'm not sure what pistol you are working on. is it the incorrect 1851 Navy .44? If so, even with a rebated cylinder it would still be incorrect. Perhaps you could say that the .44 Navy was the lost production run of that one prototype?