What type of proofs are these?
 

I know these are Imperial era marks, but could these receiver been off an Erfurt?

I can't quite make out the letters, but the firing proof, last to the right, is the type used by the Erfurt Inspector.

FN

WOW, thank you SO much, it looked like an Erfurt to me, ALL the way. SO does this mean it is an Erfurt receiver? Yes right? Or not necessarily?

Thank you.

Far left it looks like a crown RC, which is usually, but not always found on erfurts

The third acceptance stamp seems to be C/P which, according to Still's lists in Central Powers Pistols, was used only on Erfurts.

The rounded edges of the Erfurt receivers are also much more pronounced (and sloppier) than those on their DWM counterparts. Another sign that quickly identifies this as an Erfurt receiver.