I think it's overpriced

Those model years were one of the last well-made 1500 Silverado's, however that one is way over priced. Try to find one of those model years with 165,000 miles or less for $4,500-$6,000.

I don't think a gm truck with 215,000 miles for $7200 would be that good. I would choose the toyota tundra or ford f150. The silverado's all break over time and there are so many better trucks you can get for the money. They 2006 tundra is a great truck as well and will last way longer. 

have a mechanic check it out

It's overpriced. 1k less and it would be a better price.

I would offer the dealership $5200 and a cheeseburger after an independent inspection of course

Too many miles, too expensive

Also, I searched the vin number on google and found that the price is a few hundred dollars cheaper on other sites

Still, I'd look for a lower mileage vehicle