Hmmm, I don't remember where I read that they tumbled the whole knife, handle scales and all, but I think it was just from another member and I'm pretty sure they were speculating so I could be wrong.
But, I will say, looking at my own stonewashed knife with black G10, it has all the telltale marks of being stonewashed, little random hazy spots on the smooth radiused areas of the handle just like the blade has and the patterning itself and even the rivets are duller in appearance and greatly smoothed over. My satin finished knives with black G10 do not have this and the patterning on them is sharper/more defined.
So they may do the blanks first without the handles but I still think I see evidence of the handles being tumbled too.
If you have black G10 with a stonewashed blade and also one with satin you should be able to see what I'm talking about.
When you get your stonewashed canvas micarta one, let me know if the pattern is smoother than your non stonewashed ones. I'm curious.
More importantly though, I hope you do more great videos like you did of the AFBM when you get yours!