Chevrolet Neon Dealer Sign

[Smokey]

I'm looking at a Chevrolet Dealership sign that a friend has. I know its from the 30's and its a dual sided one but only had working neon on 1 side. The left side has some slight damage that wore the porcelain off that I took a pic of. Long story short, I'm interested but don't know the market on them. I don't want to shoot him in the foot with an offer or shoot myself at the same time as I don't know if it would be rude to offer him 3k or is it a 12k sign. I couldn't get great pics of it, but here are a couple of pics of it.