Bruce,
Your black kettle came out very nice, and the grates are nothing short of a miracle. I have probably been too hasty in trashing ones that showed rust. I think $60 is a fair price, given that it is all cleaned up so well. Some people actually try to sell them - and I have bought them - with used up charcoal and junk still in them. What you are working against, though, is that black kettles are very common.
That red one you posted, if cleaned up as well as your black one, would, I believe, fetch a significantly higher price. It is pretty hard to get a decent return on kettles. Having a collection of parts would help. I think you have to go for colors like red or blue vs basic black. The very old ones that have metal handles and or unusual colors are a whole different animal. Now you are in the collector market. If you can beat the WKC people to a “barn find” you don’t want to do anything but wash it nicely and flip it back out there for one of them to snatch it from you.