Unknown mirror base for mounting on spare tire in fender

[lump]

I've had this old nickel-plated mount for a rear view mirror for many years. It obviously would have been mounted on a fender-mounted spare tire. No idea what it fits, or if it might have been an aftermarket piece. The base is stamped brass, upright shaft is hollow brass, nut on top is brass, and the remainder of the mirror itself was obviously diecast metal. Does anyone have any ideas on this one? 

 

Thanks in advance for any help you can offer! 

Edited May 11, 2017 by lump (see edit history)

[roysboystoys]

I would guess accessory piece for pre 1929 autos.

Not a lot of value in that condition unless someone is trying to match one for a pair , or needs a part