Will they "work"? Yes.
Will they work well enough? Depends on the way you set them up, how many MDs you are running and how correctly your network is setup.
On the older boards, I would try dedicating one of them to be a headless core. I would set it up as a hybrid, setup your first MD, and then convert it to core only. Not running double duty should have more than enough resources for a handful of MDs.