I believe it's more likely that retail broths will be made with flavoring and msg (which they get around on the label by calling it hydrolized vegetable protein and maybe some other things.)
Making bone broth is the easiest thing in the world. After you eat dinner, throw all the leftover bones and skin and stuff into the crock pot. Add some water, salt and optional add some herbs, chopped onions and celery. 24 hours later you'll have bone broth. all you have to do is pour it through a strainer or a slotted spoon.
Female, 5'3", 49, Starting weight: 163lbs. Current weight: 135 (more or less).
Starting squat: 45lbs. Current squat: 175 x 3. Current Deadlift: 225 x 3