Lack of selection.............

[MikeP]

At one time "real collectors" turned up their noses at unit marked pieces.
BYF 41 and 42s with bakelite grips were considered "last ditch" junk.

They only made so many and lots of people still want them.
Prices are climbing and un messed with guns are getting rare.
A dearth of parts is not a good sign, either.