1969 COPO Chevelle 410 rear end

[paint4metal]

Hello all, Just joined. I am looking at a 69 COPO and checking the
numbers on the rear end. The car has a build date of 07 E in Balt.
The rear end is stamped KQ, with a date 07 2 B
The casting # is 3969278, which is according to my research a 70-72
casting #. There is no casting date on the web opposite the casting #.
Looks peculiar. Is it possible GM used a 1970 pumpkin w/o a casting
date for this 69 COPO? Thanks, Dave