Ditto on the torx screws. I'm thinkin' a gunsmith worked this gun over. Torx screws have a big advantage as Archer mentions. Before they came along, allen heads were often an option, but torx screws won't round off as easy as an allen head, especially in such small sizes.
I think, since that gun checked out so well, had I seen THAT, I'd surely paid attention to the DA trigger. You can definitely tell when a good trigger job has been done if you've felt enough N frame triggers. Sounds like a gun I might have jumped on. Hard to say, though. Like Archer says, someone might have just screwed it up and a Smith made it right again. Whatever, if it had all checked out as you say, it was probably not a gun I'd worry too much about working. Even if it needed a little work somehow, it would probably be easily fixed. I'm thinking along the lines of light primer strikes or something, new spring would probably fix it, something simple like that. There ain't much on a Smith the factory can't set right even if it doesn't work, but I think that one was probably a sleeper just going on what's said about it. Might have had some custom work on the trigger and such.