My male BCI was at 390gm a year ago. He was about 8-9 months old and 3 1/2 - 4-ish feet at the time.

My female BCI was 488gm at that time. She was about the same age, but probably closer to 4 1/2 feet. But she's a female and had hit a growth spurt the month before.

Sounds like your boy is doing just fine.