The Marketplace Rules post has the rules, and
@bcoryh is following them, and (as he said), he clarified before posting to make sure.
The "How to Buy and Sell..." post is suggestions and best practices, not rules. Including a price is generally recommended. Many buyers won't bother if you don't list one, but it isn't required.
That said, selling a Mo' Bettah is different from selling a commodity uke. I suspect most posters here are interested in the price just to ogle large numbers (I admit to being fascinated by the auctions on HMS!) Serious buyers probably want to talk to Cory about the instrument first anyway.
I'm happy to see such instruments here, even if I'm not personally interested, and I hope the best for Cory and for whoever ends up with the instrument.