I found an unknown steady rest that looks like it might fit my 9a for a good price. Seller was using it as a decoration. The one odd thing I noticed is all the ones I've seen previously have a hinge and this one just has a notch in the side.
Get a measurement of the V way width, height and depth. Then a measurement from the V to the flat to make sure it will fit your bed.
Also a measurement from the flat to the centerline to determine if it's right for your machine.
*Chances are the seller won't want to be bothered taking these measurements!