Yes you would send your knife to him for heat moulding around the knife. He says he prioritizes those orders first to minimize the turnaround time. He has a number of knives he uses as his moulds but obviously he can't have an infinite number so people have to send them in.

He also does handgun sheaths so I presume has to have the firearm to customize them too. The thing is most firearms are much more expensive than knives and there may be other transport regulations depending on the State?