I KNOW they were around in the mid-1970's, maybe before. The Oneida "nu brite" with a control for each gun was from about 1977. Older--simple all-or-none-brighteners appeared for color tubes sometime in the 1960's.
Evidently--Radio Shack even sold them a long time ago, at least for BW tubes. On ebay right now--someone is selling some brighteners, one is an Archer and one is a blue gun only tele-matic
http://www.ebay.com/itm/271574282281...84.m1423.l2649