Lew - I finally got to this project. Firstly, none of my earliest boxes, 7.65 Para or any of the Bergmann boxes appear to have ever had any code stamped on them. Out of many 7.65 Para boxes, only one had a code that I could see. Some may be faded off. Some codes were on an inside flap, while most were on the bottom of the box. I was disappointed that about half of my DWM boxes showed no code, either never there or not longer perceptible to the eye. IN the first entry below, for 6.35 mm Browning, one entry within the code was illegible and is shown with a question mark. Here’s what I cam up with. Sorry there aren’t more.
6.35 mm Browning
7.65 mm Browning
29 b 45
12 i 43 Steel case ammo
18 g 42 Steel case ammo. This code was cancelled by blackening out. Below it was code 7 w 44
7.65 mm Parabellum
9 mm Pb
266 AR “G B” headstamp, Spanish language label
645 AE Spanish language label anonymous as to maker, as was “GB” box". Obviously a DWM box
9 mm Steyr
7.63 mm Mauser (both 20-round boxes in clips - many did not have a date code or it was faded out)
9 x 25 mm Mauser “Export”
I was kind of disappointed about how poor my DWM box collection was, by the way. I just assumed I had more. I had none, for example, for 9 mm Browning Short or 9 mm Bergmann Bayard. Many others missing, I am sure. Best I could do for you, unfortunately.