I know nothing in regards to the conversion cylinder but my first thoughts were exactly what Hawg said. I have a Uberti '51 Navy (which I really like) but I've found that that is one of the things I have to keep my eye on or if the wedge is in too far, it can lock up the cylinder tight. I always try to have the wedge in "thumb tight" (thumb pressure) but I would imagine each pistol has it's individual quirks.
Congrats on the '49! I've always wanted one but to be honest, I personally have never run across one at Cabelas that I'd lay my money down on. Don't get me wrong, I'm not bad mouthing Uberti, Cabelas or anything else. It's just that the individual '49s that I've looked at when at different Cabelas (probably 5 or 6 different ones) it always seemed like there was something wrong with them. One that I looked at had terrible timing, several felt like the actions had gravel in them, etc. I just took it as a "sign" that I wasn't supposed to get one!
I just chalked it up as it was the particular pistol I was looking at as I know they are not all that way. One of these days I'll find a good one and it will come home with me.
Good luck with your '49 - you'll get it figured out and I think you'll end up with a really nice little shooter.