GARGOYLE'S source for the "Frankie = prostitute" is given above:

RANDOLOPH, VANCE Roll Me in Your Arms "Unprintable Ozark Folksongs and Folklore," Vol I, "Folksongs and Music," Edited by G. Legman, University of Arkansas Press, Fayetteville, 1992, p477-484.

Anyone doubting the "John" insinuation needs only to scan their local police blotter.

On GUEST's behalf the Historical Random House Dictionary of American Slang gives no reference to "Frankie=prostitute."