it also depends on what is available for the bike resto. I know both Denton Engineering and Elderfields make awesome bling unobtanium bits for the CRs - and a lot of the parts they make aren't available so you don't have much choice.
Ironically, it is probably easier, and maybe cheaper to build a period correct hot rod (the bike I couldn't afford in the day) than a concourse stocker (the bikes I bought and rode brand new in the day)
Allen bolts, DG pipes, aftermarket grips/bars/levers/rims/tires are easier to find than NOS parts.
If someone offered me a new stocker, or a new DG racer, I wouldn't be able to resist the DG racer. (Both for display, as I couldn't ride a NOS, or even concourse VMXr.)
I just remembered we had alloy bars available in the late 70's. Not that I could afford them.