Thanks to both of you for the information.I would suggest that the dating guides generally available for 1970s Ludwigs are not particularly accurate. They are based upon Rob Cook's chart from his The Ludwig Book. Much of the post-1972 data that Rob relied upon was provided by Paolo Sburlati and matches the information that Paolo shows in his book Ludwig - Yesterday and Today. Rob should be thanked for being one of the first to produce a dating guide that addressed this era. However, I believe that the serial number range shown for 1976 is overstated. The years 1973-75 are skipped, making it appear that no drums were produced during that period, which does not make a lot of sense. Many have relied upon Rob's guide and mistakenly believed that their drums are from 1976, when most are actually older by a year or two or three.