340 air cleaner (Fiberglass?)

So a guy I buy a lot of parts from has an air cleaner that looks exactly like a 70/1 340 air cleaner but its not metal, I think it's Fiberglass....

I'm guessing it's not factory but if it is Fiberglass, is it fuel resistant? Can Fiberglass withstand the heat of the engine?

It looks the part but I think someone is messing with me.

Anyone heard of such a thing?