Can I have your assistance please?

Below are pictures of a holographic red dot sight that was mounted on my Ruger Mark II Government Target Model when I purchased it at a pawn shop. I do not like the sight and have replaced it with iron sights. There are no markings to indicate who the manufacturer is, only what appears to be a serial number. I am attempting to identify the manufacturer and model number if at all possible so that I can determine fair market value for the sight. Your assistance would be greatly appreciated.