valve cover gasket

Hi, went to order v.c. gasket well the gasket didn't look like mine they were curved on the corners on mine one is strait so i looked up 75 skylark on a hunch and there was my gasket but both gaskets had a flat corner so i'm guessing the po put a 231 odd fire head on i know it was odd fire because it has the firing order on the valve cover now the question is this ok or do i need a 225 head thanks ed