… and your gun is not a flatgate, nor does it have a flatgate.
Welcome to the forum, stick around a while and learn, it's really a great place to get your feet wet, and if you stick around long enough, you will start to collect safes,,,, full of Ruger's. There are a bunch of enablers here.
Nice gun at a fair price, you did ok, and IMO way better than a new one. It has just the right amount of patina and the grooved Old Model Cylinder is why one wants an Old Model gun. Nice feature from days gone by. Nice Walnut Grips w/ blue escutcheons & Screw w/ pristine Medallions too.
FWIW; The ad it states; 1966 mfg, and makes no claim of being a flatgate.