What your talking about is zinc plating then a passivating chromate dip. The gold color is the dip, somtimes you used to see stuff advertised as gold
passivated. The chromate dips come in at least three colors, I think the darker the better the corrosion resistance, but my platers don't do olive or blue,
the steel on jap bikes tends to be done with olive, or does it.
I haven't tried home plating. I do have a book about it that I bought in the 70's, but every recipe calls for cyanidesomethingorother so I think ingredients may be
hard to get. I phoned a platers supply house in the midlands, basically if you get a few people who want to buy some stuff you can buy all the proprietry mixed stuff
at less than the kits cost. I am told the proprietry mixes produce better finnishes than the recipes you find in books/internet.