I don't believe the GMAT is an IQ test. I agree with shahnandan that most people can learn to do well on the GMAT through hard work and practice. Of course, if someone never learned basic math or grammar in the first place, they have a long way to go.
The GMAT does not contain mind teasers like the LAST does. I think the LSAT is more of an IQ test (if it hasn't changed in the last 9 years since I took it). It contains RC, just like the GMAT but it's passages are much longer. The LSAT has two CR sections, and the questions are generally of a tougher variety than on the GMAT. The LSAT also contains a logic games section that is pure IQ test in my opinion.
As for the GMAT, I think most college graduates could be taught to score at the 600-650 level (provided they take the time to learn basic math and grammar). To score well into the 700s probably calls for some higher level thinking and understanding of how the test is written and what the test-writers are looking for. In this sense, it's not something that can be (easily) taught to most people and might quality as an IQ test. Also, I think that reading and comprehending at a fast rate is a function of IQ, and these traits (balanced by accuracy) can help you score higher.