Pretty simple actually. Only three contractors for Zf41 were Berlin Lubecker,Mauser Borsigwalde and Mauser Berlin.
Base is a modern fabrication with the original component mfg. by Steyr.
Honestly Jeff I did not notice the the Proofs , What I was wanting to Point out is there is a Very Easy way to tell Fake Base from Original .On the Originals there is 3 Small Steps that are machined in the Original Bases and Every Repro I have ever seen is missing these 3 Steps . Best Regards