Sights for Shotgun?

Hi Ron, I could use some of your advice, and anybody else that may have some good suggestions. I recently bought a barrel for my Auto-5 Light 12 and cut it off to 20". I would like to put a set of fiber optic-type rifle sights on it. Can you recommend a set of rifle-type fiber-optics to install that a talented guy, similar to myself :lol: , could install without a bunch of drilling and/or brazing? By the way, I do not have a vented rib.