Yeah. So basically in personal experience, I find that the silver cover has a somewhat thicker coating and it's easier to fully and partially sand off. It sands smoothly, so where you do leave some, the transition between the coating and the plastic is smooth and there's no peeling. The black covers have a thinner coating, and it's sort of film-like. In other words, if you scratch any off... you basically have to remove it all. Because the film just keeps peeling off the edges where it ends, and you can't smooth it out by sanding. Only by removing completely. So more work to sand. And on the inner crevice parts, like where the openings to the keycaps are for the F-row, if you just sand the top surface, you will see the coating continue to peel off down the vertical sides. I can sometimes roll it off with my finger. It's a fair amount of careful work to sand it all away, but I'd recommend getting most of it off, as seeing this coating peel off so easily does not inspire confidence in long term durability.
Although... a thick enough coat of enamel + clear coat is durable enough in itself, and most keyboards just sit on tables, but I have OCD about that sort of thing, so I'm always nervous about the long-term durability.
I'll add comparison photos to my painting thread in a bit.
