Interesting, given the pic shows a bolt through it. He must've added that after you got yours.
I had the same concern; added the lock pin to mine the other day. Re-used the chains that came on the door handles Carey sent me. I'll probably rivet the chain end in next to the clam stay, and drop the pin in one of the spare tire mount lightening holes for storage. Then it's right there when I pop the clam open.
BTW, here's what's next: