10D Z28 BV 1031
04C Z28 BV 0418
05A L78 BU 0424
01B L72 BE 0119

The BV and BE axles seem to be dated closest to the car build.
Seems like the plants were WAITING ON 4.10 12 bolt posi's.
IIRC I don't think I have seen an original 1969 car with a 4.10 which dates further out than 2 weeks or so prior.

My 11c l78 is 11 13 BV

axle date
 

12B Van Nuys axle BT 11 27 G1