Progress!
The bolt worked out great, perfect headspace right from the get-go. The barrel, fully installed, was 5 degrees shy of the sights indexing, so new set-screw holes had ot be drilled in the barrel to retain the sights while soldering them in place. The rear sight base was assembled and indexed off an original sight leaf, the front was indexed t the rear base using parellels, and the whole thing was parellelled to the receiver flat on the underside behind the recoil lug. Worked out splendidly. (what a pile of work making the repro base work adequately though!)
Once the bases were soldered on, I checked alignment to make sure nothing had warped and the fitting of the sight ramp was still valid - it was, nothing had moved. Then the interface areas were cold blued to see if any solder was missed in cleanup. The bluing will be removed prior to hot bluing anyhow.
Now waiting for the stock to get here from Europe...
Here is the proof that I'm not going to totally pass tis off as an outright fake. The barrel came off an East German action, found it in a bin of orphan barrels at a local gun shop. Someone had removed it with a monkey wrench (I think). I left these marks in place as they indexed to the underside of the barrel and are covered when assembled. A disassembly will betray the linage of the barrel though

There were wrench marks on the exposed areas too, but those have been filed out and re-contoured - you can't tell anything was ever there. Bore on this barrel is PERFECT. I suspect it was not shot after being imported, someone took it off an action they used to build a sporter. Should make a great shooter.
Here you can see what is (IMHO) the biggest giveaway that the repro base is fake. Look at the retainer screw, there is a small gap around it. On a real base, this gap is not perceptible and the fit is tighter. The screw is real, though I may yet make a replacement that eliminates the gap.
Now some progress on prepping parts for bluing. This was a 1943/44 era extractor with a mis-matched serial. I used emery paper to remove most of it, then over-stamped the serial with new numbers in such a way that the residual marks from the old serial were covered by the new numbers. Pretty convincing huh? I went over it with coarser paper afterward ot match the rough wartime finish.
Bolt assembled for test fit.
Parts I scrounged that are correct for a byf44 awaiting bluing.
This is the TG I have on-hand. I have another on the way that is not serialized, we'll see whichever is nicer when it gets here. This one is REAL nice apart from the m/m serial number overstamped on the byf logo. Note the late war solid lock screws. These are real, not repro. I had them in my parts bin.
And finally, here is the drop-in rail I did not use, but my repro base came with it. Though maybe someone would like to see what they look like. The situate the scope too high - I'm not a fan. BBOTW surmises the Germans made a part like this. It's an error in the book - they are all fake/fantasy pieces.
