A 'yes' answer by itself isn't all that helpful, is it? There's always the next question. How big? How attached? What color?
An airdam probably won't hurt, it depends. How does the bottom of the bumper compare to the overall low point of the chassis (brackets and so forth don't count, maybe the frame rails and axles)? How gnarly is the underside?
I'd say airdam, and/or bellypan and/or airbagged suspension so you can lay frame and then pick it up to drive and let it grind. But there's also wheel spats and fences.
Apparently, one of the best things you could do is this:
Soften the radius on the front edge. The rule of thumb is 4% of the gross width, that's 3.3" for a seven foot wide vehicle.
Turn the mirrors upside down and hang them from the lower front corners of the van.