Originally Posted by ventport
Only other area that may have some would be around the furnace and furnace pipe connections. I doubt you will find any, but that would be my guess as to where it could be hiding.
If it has the original furnace, it might have some around the areas were the pilot light assembly goes into the combustion chamber, as well as the inspection port in the same area. Very small gaskets, in the range of 1/2" wide by 1 1/2" long. The fan assembly for the combustion air may also have a gasket made from the material, I am not sure. I think the gaskets to the exterior exhaust were made from spun glass, if used at all.