Regardless of what the truth/value of this story may be, one does not need more than a sharp knife to dismember/butcher a large game animal. Basic knowledge of anatomy and disjointing is easy. Any hunter who bags, tags and carries his game out of the field knows this.
Do smart watches link directly to the internet or do they use Blue tooth type links to a device nearby (like my hearing aids)? I avoid such stuff as much as possible....
Apple watches communicate with iPhones via both bluetooth and WiFi.
BUT the Saudis would have had to give him access to their network if his phone was not in bluetooth range.
It is possible that he had an Apple Watch with cellular service. If so, he could have been recording the meeting and that recording could have been sent to his phone.
So, it is possible.