Another magazine question.
 

My pistol is a 1939/42. The mag that it came with has an eagle with a 37 under it (top left of mag), and a number 122 over an eagle, with a 37 under it (bottom left of mag). The floor plate has a "G" stamped into it. The serial # is worn off real bad, but I can barely make out two digits that may match the pistols serial #. I'd like to know if you think this is the period correct magazine for my pistol. Thanks.