I found out the age of mine by going to the Remington website and emailing them the serial number off my rifle. In my case, the rifle was my grandfather's, and found out that it was built in 1967. It's a .243, and with a new scope on it last year I took my first rifle doe. I had previously taken deer by shotgun, muzzleloader, and bow, but this was the first deer by rifle (3rd season) and it was neat that I'd done it with my grandfather's rifle. My dad had also used that gun while he was growing up, so in a way I guess I was just adding some more family history.

Here is a link to the sight you're after: Remington