Personally, $250 isn't a deal NIB and I'll explain why.
You can go to Lowe's and use a $50 off of $250 coupon, plus another 5-10% with a MyLowes card (depending on their percentage promotion). My dad's was $230 new...from Lowes.
Around here...I can get 18WSM's for around $50 used, but their resale barely spikes above $150.
Warranty transfer doesn't matter. If the grill hasn't been registered, all you have to do is register it (and you're the registered owner).