It's a Silesia Stahl barrel blank finished by Steyr in 1939 as an ordinance spare. Muzzle drop looks pretty good. Congrats.
MO supplied early pattern stamped trigger guard.
Also, rear sight base is early Nähmatag as would have been supplied to Gustloff. Much more rarely seen than the Elite Diamant parts. Mike has a sweet '39 with a e/18 marked rear sight parts in the stickie.