OK so the project was to make use of some more of those mdf scraps I have and while I needed to buy the 2' x 4' top piece the rest was scrap.
I'm liking how it is working out so far. I think it will mostly stay in place but it is not physically attached I can clamp it in place if needed and I can just slide it off if I don't want it there.
Still working on finding places for everything that was on the bench before I started this project. About half done with that part.