The earliest steel 20-round magazine that I have seen is "G3 HK" over "9/59". 
Your 11/59 is correct on the "rounded" G3, and should have "12-120-1142" vertically and to the right.
The 1/62 is correct on the "rounded" G3, but should not have "12-120-1142".
Tony
Your 11/59 is correct on the "rounded" G3, and should have "12-120-1142" vertically and to the right.
The 1/62 is correct on the "rounded" G3, but should not have "12-120-1142".
Tony