I have a Winchester Model 12 I bought a few years ago and have recently pulled it out as a project. The barrel was cut to 21" and threaded for choke tubes. I plan on restocking and blueing it and using it this upcoming dove season.

It had been drilled for the front sight but one was not on it when I bought it. I now know why. Not enough metal left for the bead threads to keep the sight on.

Are this slip on high visibility sights any good? They are plastic, right? Does anyone make a steel assembly?

I would avoid the high vis sights like the plague. Anything that takes your eye off the target is bad.

The first thing I would do is be on the hunt for a longer barrel. Unless all you plan to use it for is street sweeping. NuLine Guns or Simmons is where I would start.