Looks good, price is right. Check around the tower base for hairline cracks since it's not a standard item on an escalade and looks aftermarket. Check the prop and drive shaft. Check all guages and electrical. Salt corrosion is a biggie to look for! Can't tell, and probably doesn't have perfect pass, so add that in to the price but it's easy to install on that boat.
Get a mechanic to run a compression test. Your best bet is a water test. If all checks out, you might be able to get 2 more grand off. -Good luck