Thanks Corky.
It's not just the white stem I want, but also a more modern handlebar and want the stiffness & adjustability of a threadless stem.
I bought the frame on Ebay with no stem (or headset), and I'm decking out the rest of the bike with modern, 7800 components.

Is there a headset that bridges the gap between threaded fork and threadless stem? I'm a big fan of fewer fasteners and simplicity.

It's such a beautiful bike...