I have several questions.
1) does the discrepancy between his achievement level and his grade level explain the behavior stuff? I'm trying to figure out if fixing the educational issue will also fix the behavior, or if there's more going on.
2) would this level of achievement plus the behavior stuff suggest that he needs to be in the district's differentiated gifted program? I feel like a kid this far ahead should not have been sent to reading camp for at-risk readers and since he was, there's a huge disconnect between what's possible and what's happening...
And 3) we have a gifted program in our district, beginning in 4th - will the school actually look at his recent testing results and flag him for further testing?
Welcome!
1) Very likely.
2) and 3) It depends on your district. Usually, the teacher will nominate a student for testing. Many districts allow parents to nominate as well. There definitely is a huge discrepancy between the Lexile and ?SMS scores and performance during 3rd grade in school. If the tester is well trained in gifted services, he/she may see through it but many won't.
With my personal experience, Lexile score does not carry much weight. Out of level testing like EXPLORE would. Your DS can take it through Duke TIP. And check your district policy and nominate your DS.