A fake coating will look terrible. People who choose a copper sink like its patina. If they don't like patina, they choose a different material - there are, after all, many other sink materials to choose from that do not develop patina.

You should actively avoid any copper sink that has a coating. A copper kitchen sink should have a so-called "living patina" in which the copper reacts to the elements. It will get shiny in spots when something acidic hits it and then patinate back to the dull brown and will always be mottled.

If you expect your copper sink to be shiny and pristine looking, it will not as lacquered finishes are made from things that don't receive much use and are intended to be ornamental only.

Copper also may not be for you if you want to have a uniform patina. All kinds of things can get splashed on the sink which will mess up the uniformity of appearance. And there will sometimes be stuff that you need to scrub to get rid of, and this also mess up the appearance. I love the look of copper, but I would never want it in a sink.

@kudzu9 You can't "mess up" the appearance of a copper sink with a living finish - that is the beauty of it because whatever you do it just gets the patina back pretty quickly.

And I have never had to scrub my copper sink because it isn't "white" like the Kohler enamel I had which had to be scrubbed with Bar Keepers Friend because otherwise it was discolored just from ordinary use.

Just recently I had a new housekeeper who is a VERY conscientious cleaner and even though I had told her that the sink was the color it was supposed to be, she must have forgotten because she tried to polish it. She had gotten a bit "polished" and apologized because she hadn't been able to finish - thankfully. 🤣 I was so bummed but in about a week it was back to its beautiful "mottled" living patina.

But if you want a shiny sink it is not for you - it is for people who appreciate the patina just like some people like old faded jeans/real linen and other people want shiny shoes and crisp ironed shirts.

I've replaced quite a few perfectly fine copper sinks with alternatives because people found out funk just wasn't for them. No on the coating unless you never use your sink.