This look can be duplicated.
Now that the tank is sitting on my couch, I have to say the "chrome" paint very closely resembles moderately polished alloy, which overjoys the heck out of me. I'm going for the "scrambler" look and paint over chrome IS that look, but I'm kind of chromophobic. It's kind of too cruiser-esque for me. OTOH, polished alloy?
brushed can be, but not the polished to that high of a level.
According to our experience, yes. But early in the process we discussed having the tank chromed, then painted. I have a guy here who does excellent polishing work and chrome and IIRC, his bid was $175. After discussing it, we decided we'd have better luck with paint. I don't know what they did back in the day, but every professional painter I talked to, including a PPG rep I ran into at my local autobody supply house, scratched their head and began mumbling when I asked about a primer that would be compatible with chrome.
What would really be trick, is a nickel-plated tank. My next duc (250 Monza) is going to have a nickel plated frame (a la Rickman) w/red bodywork.