If your bottle was made by Root, it should on the foot of the bottle near the bottom say (VERY SMALL LIGHTLY EMBOSSED) "ROOT" and then some space and then a 2-digit number. That'll be the date, most likely in the 1920s. Other makers could have the 2 digit date on the exact bottom, or the city it was bottled in. By WW2 and later these were ACL (painted) labels. I have one from my town on the bottom and "ROOT 25" on the heel.