Technical Straight axle spindle tap size?

Anyone know the thread size on the grease fitting holes on the spindles of a Ford straight axle? Mine were painted over and I'd like to chase them.

 

On my 40 Ford they are 1/4-28.
Before chasing, remove another similar looking grease fitting and see what die it fits, just to be sure.

 

Technically, I believe they are 1/16 pipe tap(27tpi), but using 1/4-28 is common.

 

Thanks