I’m sure even parts made in the 60s-70s are different colors and weights as batches of material varied. I wouldn’t think the differences are in any way worth the huge expense in finding a vintage kit to cannibalize.
The new ones, were made by the same family, same exact mold. How much cooler can you get in terms of lineage? That said, I‘m sure the older parts may be cleaner, as the molds would have worn over the decades.