In regard to your ds who didn't qualify for GATE based on the Raven test, it may just not have hit on his areas of strength and some kids don't do as well on group ability tests as they do on individual achievement tests.
I believe that CA uses the Raven test b/c it is supposed to be more culturally fair (being a more diverse state). The Raven doesn't have verbal sections like many other ability tests do. It hits more on visual spatial thinking, so it really is only testing one area of intelligence. This is in no way discounting your younger ds' scores! He did awesome!
I am just mentioning this b/c, if your other ds seems bright to you, he probably is and this just wasn't the test to show it. Individual ability tests (like IQ tests) have sections for visual spatial intelligence, but they also include other subtests such as verbal, quantitative, auditory and/or visual memory, and processing speed.
