Which, of course, I discovered.

And also discovered that the front mount-holes are four inches farther from the tip of the board than the rear mount-holes are from the tail of the board.

So I guess what I'm saying is...

By "centered", do you mean centered on the mount-holes based on that center mark you described, or, do you mean measurably centered between the tip and the tail of the board?

I'm guessing you mean the former.