If you were going to choose between these two cars?

The '72 hands down.
Normally I like the '70 B bodies better, but like so many have said, the RR is all original survivor. The 70 is anybody's guess & looks like it needs way too much work. On 1 hand you have a car that someone took great care of to keep it nice. On the other you have a low budget attempt to make a RR clone that isn't done & what is done is kinda sloppy. JMHO.

I personally don't think the price for the '72 is all that far out of line. Especially for an unmolested survivor. If it's worth 13K to you & you really like it, go for it!
Car are a terrible "investment" anyway. So if you are buying it to enjoy it, why not?