Good afternoon all!
Just acquired an original bug from a SK estate sale. Has black paddles, grey base. The name plate has the serial number (61619), is marked "The Vibroplex Company, Inc" but has no patent info nor location of manufacture engraved on it. Looking at WW7P's serial number list this is either ca 1918 (doubtful) or 1988 (more likely). So how do I definitively determine the age of this key?
73s,
Phil K2JPE