It does not seem to me like he is referring to the "finished program" reference class at all. There is a class of l-zombies, and finished programs that are never run are in this class, but so are unfinished programs. The finished programs are just members of the l-zombies reference class that are particularly easy to point to.

Sorry about that; I've had limited time to spend on this, and have mostly come down on the side of trying to get more of my previous thinking out there rather than replying to comments. (It's a tradeoff where neither of the options is good, but I'll try to at least improve my number of replies.) I've replied there. (Actually, now that I spent some time writing that reply, I realize that I should probably just have pointed to Coscott's existing reply in this thread.)