In that case, I believe that there is no violation of the Guaranteed Room Type, since the room type you booked was unspecified. But I might be wrong.

I am really, really picky about the location of my room, but I don't care at all about the number of beds. When making a reservation at a hotel where I stayed before, I try to remember/conclude/guess the bed configuration of the quiet corner rooms to maximize the possibility that one of them will be mine...