part identity? A/AA license plate holder?
 

http://images21.fotki.com/v833/photo...MG_2796-vi.jpg

http://images12.fotki.com/v616/photo...MG_2797-vi.jpg

I recently found this when sorting through mostly Model A parts. I have had it for about 20 years or more and do not recall getting it, but it may have come with a '28-29 closed cab body.