It is my understanding that Schwinn Paramounts were constructed using Nervex Pro lugs until the builders ran out of their supply and switched to Prugnat lugs because they required less modification(hand filing). This change was not greeted with enthusiasm and was considered temporary until the Nervex Pros again became standard. I have a chrome Paramount SN L829 -which dates it to mid 1968 with Prugnat lugs. I have not seen other frames this early with these lugs. Do I have a rare frame? 'Anyone have a timeline on Nervex - Prugnat back to Nervex Pro? thanks in advance, Rodney Handsfield, Wichita (70degrees), Kansas