It's probably a fair claim to say it's the original high-end DE razor but 'best' is subjective as mentioned earlier.I do believe you are correct (to be sold to the general public) there were hospital Stainles steel DE razors produced (US) before the AS-D1. P.
(Olaf Ramussen US Hospital Razor)
I've never used one of these. I'll probably come to you good folk to loan me one of these out of curiousity in the early part of next year.