70's Ludwig bass drum spurs

Hi all, I have a question about the bass drum spurs of the Ludwigs in the 70's..



I've seen a few different types, all based around the same fold in curve, with what seems to be different thicknesses and different tightening nuts.



Was there a cross over period where parts of newer and older ones were used?

Can you date the drums by what is being used (if original with the kit)?



Thanks in advance for any help.

70's Ludwig bass drum spurs