Looks like an early Atlanta stamp pad ...
Tonawanda stamp was gang style...
The VIN was stamped individually...I have seen later pads (May 66) with the "A" for Atlanta squeezed into the pad appearing as if the "A" was stamped in after the VIN had already stamped...I have a few atlanta pad photos that are similar to the pad that is posted. Looking at my sequence of atlanta pads, it is apparent that the font size changed at certain times in the production year...
One more thing, the "H" in the pad is correct