Poor Condition Alphabet Commercial

[airforcemajor]

Admittedly I am not knowledgeable regarding Lugers but I noticed several things that don't seem correct.

The first is the "dish" on the front right side of the receiver appears to be narrower than the corresponding dish on the left side. Would this indicate someone obliterated the proofs for some reason?

In addition, when viewed head on the front of the receiver is not the same thickness on the top as on the sides; is this normal or an indication that the top of the receiver was ground on the top?

The proof on the left side of the receiver does not look like any I have seen on this site. It appears to be just an "N" with no crown. I noticed this picture did not load so I will try again.

What is a bkiw transitional piece?

Thanks to all for your replies and information.