this is the best way to go there in apple store for checking if this model has Nvidia 8600M GT graphics then they will replace it within the 4 years of purchase of this laptop.
MacBook Pro 15-inch and 17-inch models with NVIDIA GeForce 8600M GT graphics processors
MacBook Pro (17-Inch, 2.4GHz)
MacBook Pro (15-Inch, 2.4/2.2GHz)
MacBook Pro (Early 2008)
These computers were manufactured between approximately May 2007 and September 2008.