There is no definitive way to determine that as all weapons were routed to Heer depots and directly distributed to other branches from those Heer depots as needed starting in 1942 if I remember correctly. This is also why other manufacturers have only the E/H on the side of the stock and there's no E/L or E/M on 1942 and later rifles. The only way I would see you getting a definitive answer is finding out if there was a story on if this was brought back or not. But I would likely assume Heer given the size of the Heer and their demand for rifles.