Can I ask everyone... what you would use/need a guard for?
If it's to protect the Res-C from batoning then maybe you're using the wrong knife for the job. I'm not saying the Reg isn't a great woods knife or that anyone shouldn't do whatever they want with it. I'm only saying that there is no ONE knife solution for every task out there. If you want a great 7 inch camp knife get a Tramp or Chopweiler or SOD.
However, if you need the guard for blocking another opponents knife in a fight... then I can't say a lot to that, because I've been in a total of zero knife fights. I have never thought of the Reg's handle shape as a "guard" in the sense that it keeps your hand safe from an opponent's knife. I see it as a guard in the sense that it keeps your hand safe from you own knife. On a thrust or dig the handle shape helps keep your hand from sliding up the blade especially in wet conditions.
But again, I have no experience with that either, it's just a thought.
I keep reading how everyone's concerned with the "un-reinforced guard" and keep scratching my head as to why.