well im in the resto of these and notice the stamp on inside of 8x12 clear interior hang tom march 9 rch1971
clear interior, bd march 6 71....
granitone snare march 8 71
granitone 9x13 hangtom march 8 71
granitone ft march 7 71
serial #46624,46403, 46437, 46764, 46031 bd sorry about title my keys are touchy they jumped
the years of stamp tell the story but also maybe this means the standard's have there own serial #'s dam u just touch the dates in the granitone and they smear it sucks shoot clear lacquer over them be for cleaning dont use acrylic it melts the date stamp