It is so unfortunate when people don't speak up when they buy something. Theres no way to verify if a trade actually occured then, which would reinforce if the seller was legit or if they were a scammer.
I'm sure that after the transaction is complete and the buyer has received the item both the buyer and seller will leave feedback for each other. If he just sold it the buyer probably hasn't received it yet, so it's too soon to see feedback. I don't see anything in this thread that would indicate any sort of scam.