Only if you assume that IQ is independent of altruism. Given that IQ covaries with altruism, patience, willingness to invest, willingness to trust strangers, etc, I don't see why you would make that assumption. I'm fine with believing that greater IQ also causes more cooperation and altruism and so high IQ players understand better how to exploit others but don't want to. If anything, the results suggest that the relationships may have been underestimated, because lower IQ subjects' responses will be a mix of incompetence & selfishness, adding measurement error.