I did some digging and found some information in a Dana-Spicer Information Document

"Do not change axle gear ratios on vehicles with anti-lock braking systems except in accordance
with the vehicle manufacturer's instructions.
Vehicles with anti-lock braking systems may utilize sensors and tone rings within the axle
housings to ensure the functioning of the anti-lock brakes. Improperly changing the axle
ratios may defeat the anti-lock braking system. If changing axle ratios will require changing
the location of the tone ring on the ring gear flange relative to the location of the sensor in
the axle housing, contact the OEM manufacturer for specific directions and guidelines."

So the teeth are for ABS.

Anyone have any information on how or what to measure to verify this locker fits a Dana 60?

Thanks again. John