Technical Side Mirror I.D. help

Helping a friend move, I inherited a variety of side mirrors, including this gem, which I'd love to use on my kustom truck. What is from? I'd love to find a second one...

 

Any ideas?

 

is there any writing or part #'s on the underside of the base? if so it woiuld help to post pics of them to help identify

 

Looks a little like maybe an Olds mirror from the mid-50's.....

 

two sets of #'s on underside of base... M1191 and N (in a circle) 981839... small "2" above everything...
number on rubber mount is 4533