If the threaded race and locknut go on a BSC or ITAL fork, then it is BSC/ITAL. If not, then it probably is French. With an alloy headset, don't use too much force, otherwise you _can_ thread it onto the steerer, but you'll remove quite some aluminum. I have seen somebody do that once with a Stronglight A9. The headset later gave great service for at least 70,000 miles.
Your mileage may vary.
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Jan Heine, Seattle
Editor/Publisher
Vintage Bicycle Quarterly
http://www.mindspring.com/