^ Yeah, later versions of the cover have a hole as pictured above. With the original cover it makes sense to use four posts and maybe that's why the newer engine covers use to ship with four posts. When I ordered mine, a month or two ago, it arrived with three posts and a nut, which is used to hold down the cover where the hole is.
But that has me thinking - how is the older cover secured? Surely it's not just resting on those posts?