The bolt is through it in the wrong direction.
It will probably have A33 in the casting on the opposite side shown.
It came off a red hand grinder that had a gold diamond shaped logo/decal on it. Probably old US or maybe Japanese. Could also be Tiawanese for all I know.
I bought mine at a garage sale, and it didn't have the tool rest.
The inside gears seem to be bad, but I still haven't torn it down the rest of the way.