My question is what was the original jute backing material? Al Knoch says the jute had a sound and heat deadener adhered to it. Corvette America says that it was rubber backed. Are they the same? If not, which is correct?

 

I think the answer your looking for is: 63 and 64 were rubber backed carpet used with no underlayment. 65 - 67 had a jute underlayment and no backing on the carpet.

Additionally 63 and 64 carpet sets were individual pieces. 65 - 67 carpet sets are molded to conform to the floor shape.

 

Do know if the 65 jute had a rubber backing or a heat & sound deadener attached to it?

 

It's been almost 20 years since I installed carpeting in my car but I'm pretty sure the top sheet was not rubber. From memory it seemed to be more like a bitumen impregnated heavy kraft paper on the surface of the jute padding.