Help with unknown trainer stock

[Bob in OHIO]

Trying to identify what this goes to?? I bought perhaps 15 yrs ago, anticipating KKW but nope!

There are a combinations of attributes, when combined are puzzling to ID.

• Bayo lug!
• TD disk
• Pinned bands
• Unnumbered channel (rules out Mauser Ob. IMO)
• Wood near the front of the trigger guard, has a flare for grasping a magazine? See pic 7
• Both wood and HG have B-12 penciled
• Walnut

Except for the trigger guard, I have the hardware... FYI, stock has remnants of masking tape

Any help with an ID is much appreciated

 

[pwcosol]

The underside looks pretty weird. Perhaps a stock for the Chinese TU-KKW? Apparently they started to be imported in the early 1990s and take a 5-round magazine...