help please decode 12 bolt codes

[AnobleL74]

hi,
my 1966 c10 12 bolt has casting Diff # 3896838.
tube stamp code 14A K083.
-not sure if the 1st digit is a 1 , L, or an I it could just be a symbol the stamp is not clear to read. the 4 and A are very clear.

i could not find much info on web for the diff but it looks to be made by mckinnon in Canada , nov8 1973.

i counted the teeth and it calculates to 3:07 ratio and is an non posi.

any help to decode further appreciated.
thanks Allan