I can confirm that the clamps were copper clad then blackened. I have one that's about half worn to copper and another that's nearly all black. What I'd REALLY like to know is whether or not they were on the engine when it was painted, there may have been a year to year variable, as well and an engine plant variable such as when they went from orange to blue (Windsor to Mound Road) in late 1971. I have seen a pretty fair number with engine paint over spray, almost too many to write them all off as "day two" touch up over spray jobs.
