Interesting...I am pretty sure one of mine is a 71 and the other a 72 and they are both pot metal. Sorry, I'm not sure which of those is correct. I think mine had a shorter insert side like the first picture but I don't want to steer you wrong.
Thanks for the reply, my car originally had pot metal ones too but once I found these I latched on and haven’t let go. On occasion you will see a pair on eBay but not often. There is a company that makes new fiberglass ones but I’ve had these for 25 years or more.
