Shifter Threads

I have a friend in Hong Kong redoing his entire 355. He wants to install a custom shifter knob, but doesn't know the thread size. None of his research has turned up a solid answer. Does anyone know? He was told some Ferrari's use 10mm x 1.25 for the threads, but he wants to confirm this before spending money on a custom shift knob....Any help would be appreciated...

 

Thanks Daniel