Wouldn't of thought so...if that was the case, i dare say the filler cap would pop off before the gasket was breached. Are you 100% sure its the rocker gasket an not the camshaft oilseal..?? You need to get the rocker cover on a true flat surface and check that edge, as the only pressure points for the seal along that edge come from each corner, even a slight undulation in the middle could cause a leak