It really depends on the school as to what they will accept for a gifted identification. I would not retest my youngest on the CogAT b/c I just don't think that it is the test that shows her abilities best, personally.
You can, of course, go pay a private psychologist to give him an IQ test. That's what we wound up doing with dd#2 (twice to boot!). I'd make sure that the school will accept those scores before you spend the $, though. Many schools want a combo of ability and achievement scores. Does he have any achievement scores that would qualify him for gifted services in your district?
Is it reasonable of me to say that it is in talking to Damian that you REALLY hear the gifted? Have you ever seen that in your own children?
I doubt that a school is going to accept a child into a gifted program based upon subjective criterion like him seeming gifted when you speak with him. In terms of seeing that with our own kids, I can tell you my experience.
My oldest consistently tests as gifted 98-99th percentile on every test she is given whether ability or achievement. She comes across as extremely gifted when you speak with her as well. She was a shoo in to get into gifted programming b/c there was no question from anyone as to whether she was or not.
My younger dd is highly erratic. Like I said, her IQ scores were well higher than her CogAT scores. She was tested on IQ (WISC-IV) at the end of 2nd grade privately. Her GAI (which is an estimation of IQ) came out at the 99.9th percentile. On the CogAT, she was somewhere in the upper 80s (percentile). Her group achievement scores fluctuate from the 50s to the 90s (percentiles, again). We weren't sure that she was going to get into any GT programming as a result.
We went ahead and had her retested privately on IQ and achievement at the end of 3rd to try to figure out what was going on. Her IQ score on the same test dropped to the 97th percentile which is really quite a large drop (around 20 points from a year prior) and on two other IQ tests, the scores were all over the place. The psych said that she couldn't even get a composite score on one of them b/c the variations were so wide. The individually administered achievement scores were in the 98th and 99th percentile for everything, though, so she was placed in a gifted reading class this year.
Reading isn't really where she is gifted, though. What she needs is instruction that recognizes her divergent, creative thinking style. Honestly, we aren't going to get that in a public school no matter what gifted or accelerated classes she is placed in. We're thinking outside the box for that reason and trying to see if we can figure out a way for me to make some $ from home such that I can homeschool her for a while. We can't afford to lose my income right now.
What is it that you are hoping to get for him from a gifted identification? I think that is the most important question you can ask yourself.