Wait; you want to surface mount it? I think you're going to want a double handy box and a single connected with a short nipple. Probably not a close nipple cuz you will want separate switchplates (I don't think you'll ever get a singe plate to fit two side-by-side boxes.)
Yes, it's for surface mount on a plywood backer board. I know about the boxes with removeable side plates, just used three of those for wiring in the basement for some friends who were doing a basement alteration. But for my job I need surface-mount handy boxes.
Okay, looks like I gang two boxes together. At that point, I think I'll just add another double box and have a spare switch for some future project.