Updates as promised.
When I got into the guts of this 19, it looks like a variety of people with various skills have "had a turn" at it in the past. Someone asked about the hole visible under the site, and sure enough someone had drilled and tapped a hole in the frame right above the barrel threads. The hole does NOT extend into the barrel or threads and does not seem to have caused any constriction. I am afraid that it may have weakened the frame quite a bit. Anyone have experience or strong opinions on this?
Also, someone installed a ball-lock on the crane (Kuhnhausen talks about these) and it appears to be properly done.
Other interesting or strange is that someone had resolved an endshake problem with two shims on the end of the crane: one is .001 and the other is.002, so it had quite a bit of end shake. The whole thing disassembled (some minor springs and screws are NOT shown here).
Reason I suggest different skill levels involved in the work is the spring and plunger were missing from the cylinder bolt – and I've heard that is prone to go AWOL if you don't know it's there and watch for it to jump.
Finally, the cylinder face of the yoke barrel is out of square about .003 so that needs to be faced. Otherwise, I think this is just a well worn Model 19 that can be restored to a routine shooter without too much more trouble.
My last step is going to be to check headspace and barrel gap and true when I get it reassembled. If that all comes out to spec, then it will be time to tie it to a tire and see if it's safe
Thanks all for your suggestions and advice.