It's an old PA cab. It does have the right sort of design to be a nice cab, or at least could be with the right woofer. That of course doesn't mean it is a good cab, but for $100, I'd go give it a listen.
Those sort of deals are the type of stuff I pick, repair, mod, etc. and end up with nice stuff for cheap. You do have to know the basics of design and be able to fix stuff to do that though.