Put a wanted ad in the forum for a mule drive and see what happens.
It always pays to go with a printout from the parts book when you are shopping or buy a unit that is on a tractor and take every bracket and bolt. If it is not complete, it is not worth much. You did not pay a lot for what you got and somebody will probably snap up those LoBoy brackets on eBay when the grass starts growing next Spring.
Plenty of meat of that deck- it is made from 10 gauge steel. I welded 1 inch channel on the inside lip underneath to stiffen it up after blasting. The deck is so heavy, they tend to crack along the top angle iron mounting arms from all the flexing. No complaints after decades of service, but I would make that modification if you are blasting it. I painted the bottom with POR 15 and no UV-protective topcoat since it does not get direct sunlight.