Hugh,
There are not numbers in that position on my Erfurt LP08, either. There is, however, an upper-case letter K on the frame, thusly:
Is this the position you are talking about?
Also, there are no numbers on the inside of my sideplate. There are, however, letters stammped there, an E and an H, in different places, in the same size and style as the K.
Steve,
Do I remember correctly that there are Crown/N proofs on your barrel and receiver/rails?
--Dwight