I've had "experts" tell me this for years, the theory being that Detroit doesn't do it so we shouldn't. They foretell all sorts of dire consequences, like high oil consumption, poor ring seal, etc. etc. I usually nod sagely and go ahead and oil 'em up good anyway, like just about every successful engine builder I know. We don't have the machinery to spin an engine over for a minute or two before fire-up like Detroit does (or used to do, apparently they don't anymore.)