Congrats on the find!
As for the leg sockets I wonder if the better route might actually be asking your welder buddy if he could make a replacement socket. Easiest method might to be finding a similar steel pipe and just chopping it to length. Cutting a piece of steel and trying to bend it round could be a little troublesome unless they have the right tools available. Then they could just weld the replacement socket it to the replacement patch of steel.
Good luck!