THat's a great site Nick. THanks for the tip. You're right, as usual. It doesn't show the three hole mounting type but it does talk to it.
I did a little more research. Seems 1976 was the year for the three hole attachment rack. Here is a sight that sells replacement racks either new or rebuilt.
http://www.carsteering.com/addtocart.../80-70004.html