Sir, In all due respect these signs are not "production" signs ordered by Sinclair and produced for Sinclair (or Texaco, Sohio, Standard, Ashland). I don't really understand all the different words you are trying to use (reproduced, aftermarket, etc.), but my previous statement is my opinion. I have been collecting 35 years and a lot of people will produce a lot or few signs/globes to make several hundred dollars. The "purpose" is to sell them for a little money and make some money, period. My opinion, they have no value except to decorate something.
