[mrerick]

Sure, They were applied by hand, so could be anywhere in the large open field that was milled out of the center of the plate. Here are some examples from Mauser Lugers ranging from 1937 through 1942.

Note that some plates were numbered with the first one or two digits of the serial number; some plates added one to the first one or two digits, and some plates (especially later) were not numbered inside.