If it sits, it fits, right? Base width and center height matter, beyond that, rests aren't really unique to one machine. Unless you're going for the concours numbers matching thing, with the assembler's chalk marks on the firewall and all. That's okay too, it just takes longer to find the part and the price might not be nice. You never know. But there are a lot of steady rests out there that will fit your lathe, they aren't very precise pieces of equipment. The critical alignment is done by the fingers, not the base or ring.