Goodyear Wide Tread GT E70-15 question

[AMANOCC]

From a 69 Corvette "Stingray Guidebook" by Rick Bizzoco.
UY05D81 U=1969 (year of production, Y=May, O= Goodyear (Manufacturer), 5=Gadsden,AL (Location of Plant),D8 (these two positions are noted as "size of tire" but no chart was avaiable, 1 ("type of tire" again unknown).

TCO551D T=1968, C=Sept, O=Goodyear, 5=Gadsen, 51=unknown, D=unknown.

MDUY DJA162 M=Goodyear produced domestically D=Plant code(no chart), UY=tire size (no chart), DJ=tire type (no chart), A=Internal use code(optional), 16=week of production, 2=year of production (1972,1982??) Note: "a new DOT code initiated after May 22, 1971, this was a 10 character code".

Charlie, hope this helps....Alec