Inland Shifter Identification Help

French demon said
Does somebody know the ball thread of an Inland shifter?

I would like to add a white Hurst style ball onto my '66 Inland shifter, but are they compatible?
OER White 4 Speed Shift Knob W/ 5/16"-18 SAE Thread Firebird Camaro Nova Impala | eBay

It's big. Look at the pics on thread 21. It's a hollow tube and not a solid shaft or rectangular stock like the Hurst sticks are.