Quite honestly, over-excitability and behavior issues are not required to be gifted. This is true even for HG or PG people. Most time, when a gifted kid exhibits significant emotional/behavior issues, there is often a second e going on. ADHD or anxiety are the most often culprit.

Enjoy the smooth ride. If he was tested last year as gifted, he is most likely still gifted this year. He matured. Or maybe school/life works better this year. Just enjoy it.