From the pictures but it doesn't look like he boxed the heart on several of the largest timbers and they may not be completely free of heart center either. I think they're going to move on you pretty radically for a beginning project and possibly warp beyond utility.

The current price is good but I honestly wouldn't go much higher without seeing the timbers in person or knowing the sawyer. It's his first foray into sawing for timber framing and I'm sure his buddie selected the best of the timbers for his 'kit'.