1917 Proofs

[sheepherder]

The pics below are of a mismatched Luger with a 1917 chamber date. I am curious as to what the proofs are.

The only one I can actually read is the C/RC, which in a previous post(s) both Dwight Gruber and Ron Wood identify as 'revisions commission'.

What are each proof, and what does the revisions commission stamp signify???

I'm sorry but I can't tell if one is a C/GB and one a C/F...The third one doesn't even look like a crown...Those scriptive letters really confuse me...

(BTW: The mismatched parts it came with [it was disassembled, PO had started to polish it] had both an Erfurt and a DWM middle toggle link...Any way to tell which is correct? It does have the 'notch'.)