The early and short growth spurt seems unlikely. As near as I can figure it’s possible, but something like 99% percentile, if that.
Either your measurements are off, easy enough to do with so many variables, or the dates are off, or he had an atypical growth spike.
Just to muddy the waters a bit more, maybe he looked chubby because of a glandular problem? That might affect growth rate.
“maybe he looked chubby because of a glandular problem? That might affect growth rate.”
Not necessarily.My grandson went through a very chubby period from around 11-14. Then he started shooting up to about 6’4” and thinned out completely. You would never believe the earlier pictures are him if you didn’t see it happen. I’m also pretty sure of my measurements. At most I think there could be about a 1.5” variable.