Miles - If the "they" you mean is Flatout, then yes, it is the only gasket they make for the OHC. I'd like to get them to make a head gasket, too, but the tooling costs and the relatively low volumes will probably drive the price up out of reach.
Other companies also make that gasket, such as Clifford and Victor. But with Clifford, the wait to get it would be pretty long, and I don't even know if Victor still makes it. (I have an old catalog number from them, but that's about it.)
