BD_01
They are excellent guns and fun as hell to shoot! I got mine used about 15 years ago and I’ve put a ton of rounds through it. I just recently cleaned it up real good and refinished the grips.
That sight is a Vortex Venom and it comes with the low mount for a rail, there’s other mounts you can buy separately. The Venom gets a range of reviews but that seems to be par for most of Vortex products. Its not the best but it’s compact, easy to operate, has a great battery life and is covered with the lifetime warranty. Cons are the dot is fuzzy but I notice more indoors than outside and the screen is a touch small, I wish it was larger for faster sight acquisition. Other than that, if you can get a good sale price on it, I wouldn’t hesitate to try it out.