I looked for that information for a while and couldn't find it. Ended up getting an Onyx cover, and absolutely no where on the packaging, or the cover itself does it say where it's made. So I'm assuming China.
I asked RPI and they haven't answered me, I bought their cover for my Grandsport today from e bay and the reason I was asking was to know if I had to pay duty and there is a fee so I imagine it is made other than USA!
ebay international shipping typically includes all duty/fees. It's one of the reasons I buy some things from ebay stores instead of typical website retailers.