Looks like 111 to me too... Using my extensive CSI skillz, looks like it was applied by a right-handed person that arc/rolled the stamp a bit from left to right.
I guess it could indicate a Jan 1 or Nov 11 date?
..of course, that assumes the strainer is original to the drum.
To the best of my knowledge, Date Codes just have to be figured out.
"811" would be interpreted as 1981, January (81-1)...because I don't think they were date coding in August of 1911 ( ).
Elvis, do yourself a favor and procure a copy of Rick Gier's "Serial Number Based Dating Guide for Vintage Ludwig Drums". The 111 ink stamp in this drum is most likely not a date code. The badge and serial 3121xxx are expected for ~'83 - '84. Also, the strainer is most likely a replacement.