I went out to take photos and pulled the dynamic jaw off, I hit the jaws with a wire wheel and I don't see screws or pins. There is a good 3/8" of slop between the screw and the dynamic jaw and the threads in the body are extremely worn.
The jaws log up close to square so I think I will leave this one alone and use it as is and continue the search for a medium to large vise in better condition.