Vintage? Omega Automatic Seamaster De Ville

I don't remember how I acquired this watch, but I've had it for quite sometime with hopes of restoring it. I don't know much about the watch and was hoping you guys could help. I don't see any other obvious markings on the watch. I am clueless as to how one would open it or if I should even try. Perhaps that should be left to a professional. The band is busted. I looked up the patent # listed on the band, here is the link.I guess my first question, is it real? What year was it made?There seem