Possible Soligor code system:
First number = Maker
Second number = Decade
Third number = Year
1 = Tokina
2 = Sun
3 = Sun
4 = Sun
5 = ??? (perhaps Samyang)
6 = Komine
7 = Sun
8 = Tokina
9 = Kobori
31 = ??? *
A = Komura #
H4 = Kawanon ? #
H5 = Komine #
H6 = Komine #
H7= Tokina #
H37 = Kawanon? #
M = ??? #
N = ??? #
R = ??? #
T = Tamron #
* Six digit lens date code unknown.
# Letter code lens date code unknown.
"H" prefix brands: Lentar / Focal / Soligor / Sun / Vemar
Soligor lenses were also branded and sold as: Reflex, Super Carenar, Prinzflex, Weltblick, Mirage, Infotar, Hanimar, Flexar, Elicar,Derek Gardenar, Porst and possibly Bushnell (Bausch & Lomb ), J.C. Penny, Pallas, Berroflex and Aetna.
References: