I think I have a factory cover for a 2000S head. It was on it when I bought it a few years ago, fits like a glove, no Sunn logo on it, black vinyl with white piping if I remember correctly. I'm sure there's no manufacturer logo either, but I'll look more closely at it the next time I get down to my shop.
I'd like to get covers for everything, if the price can be kept realistic!