Please remember that tires also have a shelf life of 4 years maximum. 2008 tires, regardless of km driven, should have been taken out of service in 2012. 2009 tires should be taken out of service in 2013.
This is a safety issue and most of the people disregard this fact. The problem becomes when you brake hard after running at high speed for some time - when the tires are warm..!!!
This is a safety advice. Nothing against the seller.