68-71 or 72 and up bellhousing ball stud?

This may be a stupid question but..... I'm putting a 4-speed a833 in a 72 demon. I need to buy a Z-bar service kit but not sure which to buy. The engine, trany and bellhousing are dated 71 which could be correct for a 71 or early 72. Should I buy a 71 or 72 kit that has a different bellhousing ball stud or does it matter?

ball stud 71.jpg

ball stud 72.jpg