Well the saga has finally come full circle.
I did buy an L&R 900 flint lock to replace the percussion with.
I had to open up the inletting in a few places, had to move the trigger back a half inch but overall it was a lot of fun and some great experience for me. The removed bolster was threaded with 3/8 x 16 pitch threads, for which I could find no liner of course.
I went the hardened steel allen set method which I could get in 3/8 x 16 and shaved it down to the right thickness (top and bottom material removal). I drilled a 1/16 flash hole in it and counter drilled a relief cone into the back of it (
@Zonie - thanks for the info!)
After fitting the new lock into it's final resting place I tackled the lock bolt issue.
SInce the original gunmaker had drilled the lock bolt hole at a slight angle and used a very small screw (6-40 thread) I used the same guide hole through the stock, opened it up enough for an 8-32 thread bolt and clamped the lock into place. I drilled the hole in the lock plate from the offside of the gun so the hole would be perfectly aligned. SO now it's done. The other miscellaneous small issues were corrected. I will take it out and make sure everything functions as it should and when winter gets here and I am shut in I will take the lock back down and polish it a good finish and brown it to match the barrel. I will also touch up the wood finish in a couple of spots where I had to relieve the wood to allow the lock to fit properly and for the hammer to fall freely.
Since my investment in the gun originally was very reasonable (I spent more on the new lock, new barrel lugs and cleaning supplies than I did the whole gun) I think the gun came out OK. It was a great learning experience for me, and a lot of fun getting to this point.
The WM Large barrel has already proven itself to be a tack driver and the curly maple stock is an eye catcher.
@rich pierce - If you still want the old lock and broken parts PM me your mailing address and I'll send then your way.