I've got the McDowell book on conversions, which is probably the best authority on the original guns. I was in error. I think that the most common of the Remington conversions, and this is just from memory, was the .46 caliber rimfire without a loading gate. It seems that there were many different conversions though and that some had not only cuts but loading gates. If it were me, that's what I'd go for too. If you get the .45 Colt with the cut and loading gate, you'll be good to go, both historically and practically.
