You have an older S&W that someone has significantly customized. The grips were replaced with what are probably from King's gunshop out in California. This may also be the source of the aftermarket adjustable rear sight added to what was once a fix-sighter gun. It this a 22 Magnum caliber as the barrel indicates?
I do not know about the multiple markings on the barrel. Strange.
Your gun is not worth much at all, as collectors have zero interest in old non-originals heavily customized, and most shooters would not find it very appealing either. Keep it, shoot it, and pass it down. I'd clean it up but not bother to refinish.