Were you the first to send him a pm? Saying dibs or claimed means very little itt. And seller stated he'd prefer to sell as a set, so claiming dibs on part of sets really has no effect. Even if the whole set is spoken for, it's a lot easier to deal with one person than multi people.
Dealer buttons not sold as set.
But it's all good. Moving on.
Fwiw. 'Dibs'. 'Claimed' or 'I'll take it'. Will always be honored by myself in ANY transaction.
Matt b.