Were there some extra pieces of metal floating around when you disassembled it? Were the screw slots altered as if it has been opened prior? Unless the original custodian had it altered, I have serious reservations that it was modified after that? Everyone else would be scared to death of the action. I would say that triggers & other components were used from typical production, which may or may not have additional holes, notches.
Have you spoken w/ Larry Schuknecht the custodian of Dietrich Apel's >>German Hunting Guns<< website? If anyone would know he would.
Serbus,
Raimey
rse