Well,, it depends,,,!
Some of the earlier Single-Sixes with a skinny trigger cost a bit more to unconvert,, but on the average,, $50-$75 should get you a set of internal parts. Then,, it's USUALLY just a matter of swapping out the parts.
I guess somebody lost the original parts. When Ruger does the conversion they always return the original parts. They did on mine.
However, after shooting the gun for several years after the conversion, I couldn't stand the action. It just didn't feel right and wasn't as good as the original parts were. So, I took it in to my local gunsmith and asked him to work on it. He said no. He told me that the conversion parts did not respond well to tinkering. He told me to simply convert it back since I had the original parts. So, I had him do it. He did some work on the action at the same time.
My 3-screw is back to it's original configuration, improved, has been for a long time now, and I still love it.
The only regret I have is what I had done to the barrel.:roll: It was originally a 6.5". Years ago I wanted a 4.625, couldn't afford another gun, so I had this one lopped off. The gunsmith did a real nice job on it, but now it's not original. I still love the gun, but wish I hadn't done that now.
But, back to subject at hand. If you can find the owner who originally had the conversion done, he might still have the original parts.
good information above and yes, the best is to try and find the "original" parts to THAT gun, to insure the proper timing/lockup...yes, you can still do it but never know just what you may be buying, have seen some parts kits lately that they put "bad" parts in them , like broken hammer notches, chipped hands, broken 'sear' on the trigger...never know when you will buy a "pig in a poke" so 'caveat emptor'......
Broken pawl spring (used another one), not sure of part but the hammer internal spring was missing the key to hold it in place(used piece off a broken drill bit), and some extra parts that had me looking and scratching my head. The parts don't go to it, not sure what they go to either.
Mines a 5 digit that the owners future wife made him send it in to convert so he could sell it. Kinda funny he knew it was worth more as is but did it anyway. When I spotted that it was done he told me the story and said "aww something it, just give me $100 and get it out of my sight".