I bought I think 5 of the red ones because I like red jigs and don't really paint much red myself.. so I threw them in a slot in my terminal tackle box since it was on top of the pile of gear and figured I'd put them in my tungsten box when I was on the lake. Ride to the lake, then a 200 yard walk onto the lake.. almost all of them were chipped. Havent touched a widow maker lure since.
I don't know how they are made, I seem to remember a spot on the hook where it was bare.. so probably hung and dipped in something. I'd guess dykem would work well but haven't tried it. We used to dye hooks red and blue with that stuff but it scratches easy without a clear coat.
You can achieve basically the same effect by painting raw tungsten with a candy color airbrush paint.