KOT, It sounds like the fixtures were kept; the fluorescent ballasts were changed to LED drivers, which the light manufacturer might have called ballasts so they wouldn't have to educate anybody; and the LED "bulbs" fit into the fluorescent fixture's connecting pins.
All LEDs are 2 to 3 volt DC devices that MUST have something to change the 120VAC to their level. Your "if" is true: They can't operate off of fluorescent ballasts.
A good answer is easier with a clear question giving the make and model of everything. "The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
