1982 gmc 3/4 ton 4x4 with older 350 engine. Help with engine block date code

[Joemt]

We have looked and can't quite nail down the year for certain. Numbers we have:

T0209CMJ = 1974 CMJ  350  t4OO police  -  4  full size   or  1980 CMJ  305  automatic trans. H  -  -  full size/Camaro
3970014      = 1970 - 76   350

A15 76   IS this the date code?  If so is it saying 76 and how does that fit the 74 police spec?

[jg1977c20]

this is the correct info          T0209CMJ = 1974 CMJ  350  t4OO police  -  4  full size

to elaborate more it was built at the Tonawanda Plant  FEB 9th ( CMJ ) indicates it is a t400 used installed for police and it will be a 4bolt main

the vin#3970014 indicates the block only was used from 1968 - 1979