The Bacon Banjo Co. of Groton CT. was started by Fred Bacon in Vermont in 1905 and Banjoleles were part of their catalogue prior to WW2. In the beginning Bacon sold Banjos produced by Vega, Lange and possibly others, but in 1913 Bacon started to produce their own Banjos and well as selling rebranded ones. In 1920 they started production of Mandolins as well.

In 1922 Bacon was joined by David L. Day, a senior designer from Vega and some say the company became Bacon & Day. It didn't, although the terms Bacon & Day and B&D appears in some of the advertising and on some of the headstocks thereafter. In 1930 they added the Senorita line of instruments to the catalogue that included Guitars and Ukuleles. 

In 1938 a hurricane closed the Bacon works at Groton and the instrument production was taken over by Gretsch. In 1940 Gretsch purchased the Bacon name and from that time on, (to the late 1960's) Bacon was just a Gretsch brand name, (Gretsch certainly produced 5 string Banjos branded Bacon in this period but I don't think they ever made Bacon Banjoleles?)