Robert,
If I had the gun you have I would just keep like it is.
If you need a 22lr cylinder keep a eye on ebay ,just put in ruger parts.
Have you tried shooting 22 lr in the 22mag cylinder.I know it is not the best thing to do.I got a used single six one time.Shot a of cylinders full of 22lr and went to switch cylinders and found out I had the wrong one in it for the ammo.Both cylinders are fluted with no marks on them.
Like was said,If you ship it to Ruger they will do whatever they want once they get your gun.
I also sent them a old super blackhawk.The gun was well broken in with lots of marks from years of use. Every nick and scratch had a story to go with it.
It may have been my fault for not telling them not to,but the gun came back with a black blue job and new grips.Trigger was back to their factory spec.
I was not happy with it after that and traded it off.
Just my 2 cent on it.
Later
Wilbe Lead