Arthur, the Blue dot is different than the chrome. The Blue dot has 2 set screws on the cross bar that get released and the cell simply unscrews.
The chrome has a knerled ring behind the cross bar, that has to be released, then the cell will turn. I tried my old chrome but it's frozen solid and I'd have to take a wrench to it to break it lose.
BTW The 2 small set screws of the Chrome will release a beauty ring at the base of the front cell.
The Chrome i s not much different than the newer black version. Newer coatings n maybe some increase in contrast, I really can't see the difference, quality in build is the same as well.