I found this about Knupp Auto Co. in Greenville, Ohio.
https://www.facebook.com/groups/greenvilleohio/posts/24743338405321045/No mention, however, that they were a CHEVROLET dealer. The CHEVROLET logo on the subject sign is from the 1913 to 1933 period. However, the sign's logo is NOT an exact portrayal of the true "official" CHEV logo from that period. The type face is a little off compared with what is shown online in articles about "the evolution of the CHEVROLET logo".
All that being said, I have two food-for-thought questions: First, if original, what would have been the practical use of this 11" x 7" sign? Second, if a reproduction, what in the heck would the market be for such a specialized appeal, small sign, as has already been asked?
Just thought of a third question, and this one is for the original poster. Why is your "friend" who sold you this sign able to swear that the sign is original? You might want to probe him gently for more information about how the sign came into his possession, and the reason he is so confident it's the real deal. Hmm...I wonder why he decided to sell it.
The plot further thickens when you go to the Worthpoint prior auction results site and find that three of these exact same signs have been sold by auction in the past. A link to Worthpoint is shown below. However, I don't have a Worthpoint subscription, so I'm not able to see any details on these prior auctions, or the final prices realized. John
https://www.worthpoint.com/worthopedia/chevrolet-chevy-sales-service-2020869817
