Did some more investigating, inspection and correction on the machine. First, the tension discs were a mix or one top and one side disc. Had spare top discs and fixed that. The leather washer that belongs under the bottom disc was also missing. Made one.
Drove the pin out of the piston and removed it and the check lever. Number on the piston 2231, indicates that it is from a 29K71. The correct piston for my machine is a 81860. The check lever is correct for my machine. The driving lever for both the 70 and 71 machines are the same 82220 (typo on 29K70 parts diagram. Shows it as 8222C, but parts list shows 82220). I tried to find the number on the driving lever, but suspect it is on one of the non-painted surfaces, probably where the Joint Pin goes so I'm going to assume for now it is correct for my machine. The threaded area for the check lever tension stud is counterbored, which indicates to me it was intended for a stud and not a screw since the spring covers the counterbore.
My options are to get a new piston assembly for my machine or the missing parts for the piston I have. I could make them, but the diagram detail is bad. So, I know how many parts there are and can guess based upon how I think it should work how each is configured. But would be just that, an somewhat educated guess.
I'll try the parts outfits for those part numbers to see if they have them, or at least photos of them.
regards,
Rob