They sort of remind me car audio subs I've seen before. By the look, I would not expect them to be good for bass guitar use, but you never know. If I was in need of a cab, and the rest of it seemed to be in okay shape, I would consider screwing and gluing a new plywood baffle right over the busted one, as long as I could get the cab cheap enough.
If it works, you should still be able to get some idea of what they will sound like. Does it sound like the speakers have any middle and high end frequency response, or do they sound muffled? Does it seem like the speakers are sensitive enough, as in, does it seem like you can get decent volume with your amp? If that's what you have available, the speakers seem okay, and you need a cab, get it cheap. Otherwise, and I could be wrong, but I don't think those speakers are anything special.
