Coca Cola sign

Wondering if anyone can tell me how old my sign is? and what it might be worth? Looks to be masonite with a piece of plate glass over the top of it. Brackets that look to be rivetted in to the wood at each corner, holding a clip that holds the glass onto the front.
Hardware that has rings that swivel, that wire attaches to, wire may not be original. The words Trade mark and the letter R in a circle appear at the end of the Coca tail , under the C in Cola