As ChiefShotguns states Wirnsberger is possible "the" source. Nobili's "Austrian & German guns & rifles" also is a later Contiental source version.
Regarding date codes, Zella-Mehlis began around the turn of the century with a 3 or 4 digit number followed by Suhl in September of 1923. So if the longarm was proved in December of 1923 the stamp would be "1223". And I think it was after the 1968 revisions, and possibly only in West Germany, letter of the alphabet could also be used with 0 to 9 being represented by "A" to "K".
Choke is marked by "Crown" over "W" noting a constriction of 0.2mm, I think. It's an "all or nothing" mark. If it has less than 0.2mm, then there isn't a stamp. Equal to or greater than 0.2mm = a "Crown" over "W" stamp with degree not noted.
Kind Regards,
Raimey
rse
