New to the website. Been collecting for a few months. I have an opportunity to purchase one of these. A friend came across these. From an older gentleman that used to work for Red Giant Oil in Council Bluffs, IA. 8 inches dia., good shelving, some "fish eyes" on the back. No scratches, one has a small chip on edge. These look authentic to me. Mint(?) condition. Would anyone have an idea what the worth of each is. Maybe a little history if that is allowed here. Thank you.