The guns in the OP are nickel plated.
The first one is far too old for stainless.
Colt did not make any stainless Mk IV Series 70s and the second gun has the sandblasted walnut grips of the model and the third has the early "billboard" roll marks not in the current "reissue."
The shine comes from the polishing BEFORE the plating. Plating doesn't cover flaws, it emphasizes them.
You can get stainless just as shiny, look at a Ruger Vaquero or Colt Python Elite.
The tone is different to a practiced eye, but shiny is shiny to most.
I have a few facts and a lot of opinions.
Last edited by Jim Watson; 02-12-2013 at 18:42..