Ring Gear ID???????

[Mr. Chevy]

Just cracked open the rear of a 12 bolt in a 69 Chevelle, open rear end, and the large ring gear has the number 46 ink stamped on it.. Also looks like there might be a "B" with a circle around it in front of this 46. The rear end code on the axle tube says the rear is a 3:31..

Anyone have any idea what this ink stamp on the large ring gear deliniates??? I don't think the rear end was ever messed with, appears to be all original untouched.. I couldn't find any other numbers stamped on the large ring gear..

Thanks....... Rich

[69L72RS]

Inspection mark.
The gear part numbers are probably stamped on the flat surface on the back of the gear instead of the OD of the ring.

[69L72RS]

partial stamp

These pics are from Alan's COPO gearset.

[Alss]

my 4.10 (4-69) (non-copo) gear set has the date code stamped on the end of the gear not on the flat,...were the service parts done differently?