EOD - you are correct of course. It goes without saying that wartime expediencies often take precedent over normal practices. I think, though, it is more likely military coded items were used by “forces of the interior” (police, political etc.), which certainly happened, than civilian marked equipment going to the Army, where it could be encountered and acquired by enemy forces.
The one I always thought was funny were the very late Walther PP .32 Pistols, that had no markings on the left side of the slide, where it was the norm to put the full factory name, and just “ac” on the right side of the slide. Of course, the code is to conceal the manufacturer. However, even though those pistol of this variation that I have seen had rather crude, almost hand-checkering in lot, and very spares (big diamonds), the went to the trouble of stamping the Walther Banner trademark into them. That for use on a coded weapon, thereby identifying the code. Thanks Mr. Walther!
Of course, some weapons were so famous and so well-known to be the product of one company, such as the Walther PP and the Browning P-35(b) (FN Model GP), that for most of the war, even those supplied to the military had the full commercial markings. I suppose there were other cases of that with other equipment, although I can’t think of any important ammo examples. Most of the 7.65 Browning and 9 mm Kurz that went to the military had the commercial headstamps, although there were codes in both - “dou.” on 9 mm K and 7.65 Br, and “aux” on 7.65 Br (perhaps other unimportant rounds that are slipping my mind, or what’s left of it, right now.