I have to agree that he seems much more intelligent than a score in the 1000s would indicate. But it's not an IQ score. It's possible he goofed off during the SAT's (when puberty was distracting him) and used his sports, activities, essay and connections to get admitted, but then hauled some butt when he finally got into university -- he does seem motivated by personal competition. Who knows?
Extraneous factors can enter in. I took my SATs on the worst day of my cycle, and believe I could have done 500 to 1000 points higher if it had been otherwise. Even as it was, I scored higher than Dubya, who ostensibly scored higher than Clinton.
I know someone who went hungover (or still drunk) to take the SAT and still scored a nearly perfect 1600. I don’t think someone who’s really highly intelligent could do a 1000-ish under darn near any circumstances.