[SCOTI]

This is a subjective question. Is there a need to use the later 73-up stuff? No, but...

Some people want to install the OE style 73-up rubber bushings to get a smother ride resulting from the thicker rubber bushing/metal shell housing style of bushing.

Others swap to the 73-up stuff for the ability to use Poly bushings for 'better' performance using that same metal shell housing style of bushing.

The original 72 bushings are rubber lined steel & designed to pivot via the internal threads. I like to think of the OE 63-72 design as a budget Delrin set-up (it pivots freely & is not all cushy).

So, to answer your question is to follow the ride quality you desire.