Jackie and All,
I think Chuck Schmid said (sorry if I misquote!) not to go according to old catalogs, etc., but the Motobecane catalogs show Nervex Professional lugs last appeared on the Grand Record (and Grand Jubilee as well) in 1977. Starting in 1978, they used Bocama Professional lugs (previously used on Le Champion and Team Champion in '77). The Bocamas didn't have the "curly" design as did the Nervex Professional.
This brings a question to my mind, and perhaps the framebuilders on the List can provide some insight: It seems many folks are all "excited" over the appearance of the Nervex Professional lugs, yet none of the manufacturers seemed to offer these on their "Professional" framesets, but rather chose Prugnat or Bocama or Dubois Comp..or....???? Do the Nervex Professional lugs not provide as strong a joining as a more plain lug?
Thanks,
Chuck Brooks
Malta (rain stopped) NY