Didn't sell

There was a 250k bid, but it didn't make the reserve. They did ask the bidder to see them after the auction, so maybe they cut a deal. That's sometimes how auctions work.

I assume the seller's premium would have been around 20% or $60,000 on the minimum bid.
Probably there would have been a buyer's premium as well say 10% or $30,000 on the minimum bid.
The auction house have would pocketed about $90,000 on a successful minimum bid of $300,000

A $250,000 offer doesn't look too bad for either party, unless the auction contract has some a clause forbidding post-auction deals on unsold items by the auction house.
The seller would save $10,000 and the buyer would save $80,000

I'm sure there is some clause, but the auction house could still negotiate something in the middle between the high bidder and the reserve. I know at least one Apple-1 that happened to a few years back.