Ian,
On mine the nearside fixing is a nut and bolt.
The offside is 5/16 BSF into the frame.
The spacer is a simple top hat that is slightly wider than the stand casting.
The idea is that the spacer is clamped firmly to the frame and the stand pivots on the spacer.
Ken Lack made up my stand for me from spares scheme castings and machined new spacers to suit.
He also supplied the 2 bolts and a nut so I assume that was standard.
However, as I have found out, “standard” is a very loose term when dealing with Scotts.
Especially when dealing with the very last bikes they produced where it seems anything at hand was used to get another unit finished.
Regards
Steve