2005 Ford Mustang flood vehicle

There is a 2005 low flood mustang for sale in my erea but the car is originally from california. I briefly listened to the engine which seems to run great, and there were no check engine lights or anything, although the oil did have a brownish look. I spoke to the seller and he said there were no electrical problems so far and that he changed all the fluids. He also stated that at first the car smoked a lil but he had to clean a lil water from the valve train or something. My question is do you think the oil will come clean if I change it a few times, do you think the car will begin to smoke afterwards and what else should I look for before I purchase?