Kelsey Hayes setup lower ball joint to spindle bolts

The op, guy in Australia, is using one picture of mine, of a disc brake set up that eventually will be put up for sale.
Have a couple in front of that set ready to go, and are currently being advertised, for sale.

The op is asking about the BALL JOINT to spindle mounting bolts.
What's the big deal anyway, with using a bolt that was manufactured probably 45 years ago?
Just use a grade 8 bolt, 9/16 x 18 fine thread, and your car is never going to know any different.

Why get so anal over a manufactures style of bolt, in the first place?
I could never figure that out.
But to each his own, i guess, and I'm not going to loose any sleep over it.
As long as it works for functionality, whats the big deal, who cares?