My 125L's engine is sprayed in cheap, crappy Dulux semi-gloss black. It isn't a perfect match, but perfectly acceptable for a race bike - definitely much better than gloss or matt would be.
The last YZ490 was 89 or early 1990s??? The WR500 came out in 1993 or 94, and there had been a year or two gap between it and the last YZ490.
They stopped making the 490 because they were hopelessly outdated and sales figures were in the single digits.
This post would be a lot easier if I'd had less beers. I reserve the right to have ballsed it up badly.