Glad you got it sorted and offers still open to anyone if I find that form, but currently as long as its properly declared it should get through even...
If i was in your situation i would, if i have a lathe bore out the 28 tpi thread and press fit a tight insert treaded for 20 tpi, but i would have to...
There's a lad called Nath92 who can do wonders with wooden stocks from repairs to refinishing.
If you Google his name you should find some videos of...