I found a set of armrests with the wells or "cups" in them. I would only buy them because I need the cups. It says they fit 70-74 cuda. I know '70 and I think '71 were metal and the latter were plastic. Is there a difference in the design or is it the same and just a different material...will they fit a '72 armrest regardless of year? Is there a difference between a cuda and barracuda armrest?