Mjozefow can make you a beautiful pair of replacement jaws, no problem. Check it carefully to see if it has any broken pieces, cracks, or weld repairs. If not, this is a very manageable restoration project. Autopts, Mjozefow, and others can walk you through the process very well.
Spare parts will likely have to come from other vises which were damaged beyond repair, and are not easy to find. But some pieces can be made.
Nice vise. Good luck!