7 1/4 rear end tag

I have a 65 Barracuda with the 7 1/4 rear end in it. Originally a 2 barrel car it now has a built 273 Commando in it. It’s a factory 4 speed car.

The rear end tag is present attached by one of the top bolts, but there is no ratio stamped on the tag.

However there is a single perfectly round punch out hole in the center of the tag. Does anyone know if / what this punch hole signifies?

It has to be there for a reason.