I am not sure whether it's known in America or not, but in Russia it is. Kovalchuk's actual age is 2 years more than is indicated in his documents. It was a common practice in Russian youth hockey in the 90s and early 2000s.
So, his age is showing in an unsurprising fashion.

— Slava Malamud (@SlavaMalamud) December 17, 2019