Maybe carefully razor blading the pad off of a new repro one will get you closer (better than nothing) but would be a big effort and won't look exact.
The new repro bars foam pad appearance finish don't even come close to the original finish look. The repro foam looks like it was sprayed with "Flex Seal" of TV fame.
I would rather live with a pad with a little damage like from a fire extinguish mounting etc. then the cheesy shiny look that the repro bar has . The repro bar is physically made close . It is the finish that is lacking. Replacing the entire bar is the best solution given the facts IMO. It may not be the cheapest way unfortunately. It is however the cheapest way to get the best look especially when you consider , time ,money ,stress ,personal satisfaction etc. IMO. Roll bars come up for sale occasionally. Heck a couple in the for sale section of this forum . FYI 67 and 68 roll bars have different inertia real brackets compared to each other.