The gun seems to be a Citori 625 with ported barrels. So the smoke is coming from a port in the barrel. That is to help fight barrel rise and lessen the recoil.
I've been challenging people all over the net on this. Maybe this time I'll make a difference.
Doubtful though.
You could be right. None of us really knows for sure.
Regardless, he doesn't look like somebody who shoots "all the time" to me.