Just checked Barnes' 'Cartridges of the World', and there's no mention of an 'identifier' such as that.
So - I checked a copy of TM 9-1305-200 - 'Small Arms Ammunition' - and that features the various issued .38 caliber ammunition of the armed forces.
Nothing there, either.
In checking actual military headstamps - if the ammunition was commercially-procured, it will feature the manufacturer's commercial headstamp.
If it's contracted for the military - it's headstamp will have the initials of the manufacturer and the last two digits of the date of manufacture.
Now, that's for the cartridge cases.
Since the military's M41 ammunition was jacketed hardball - no one with any sense is reloading for that round.
I'd take a good look at an Ideal catalog to see what they say.
Vaya,
Scouts Out!