German writing question

[BILLG128]

Can someone tell me what the numerals after the signatureAttachment 1404878 means on these papers. One is OIIIC and the other is UIIIC.

Thanks

[drmessimer]

BILLG128, I have a copy of U.S. Army Intelligence Service, Special Series Nr. 12, German Military Abbreviations, 1943. The manual was produced to help intelligence officers interpret German documents. Working in the single letter abbreviation sections for “O” and “C” the OIIIC might imply that Hermann Geyer was some sort of officer candidate. Among the “O” listings is Offizier and among the “C” listings there is Kandidat. I cannot find anything in the “U” listings that would suggest a similar connection. The III is, as one would expect, the Roman numeral for 3rd. But I cannot find a connection with III C specifically, such as III R.A., which would be 3rd regiment artillery. Could you post a photo that shows the entire address on the envelope? That might provide a clue. Dwight