I've gone for a mix and match approach to my Klein build. I wanted it to be the bike it would have been if it had been in my possesion since new. As with any bike I've had, some for a good few years, stuff that works and doesn't break stays. Other parts are replaced with more modern stuff if it improves the way the bike rides, makes it work better or just look good on it. The way I see it, unless you are going for a specific time accurate build, as long as you are keeping a bit of history alive go for it.