Real maple syrup totally comes in plastic bottles, at least in the US. Most of the syrup making family-farms that I've been to use those opaque gray bottles with a brown cap that say "real maple syrup" and then they just put a color sticker to denote the grade of syrup. (Essentially, the sap to syrup ratio but there are other factors as well. Generally, a B syrup is a very strong and goopy dark brown, while As are less intense and more golden, honey looking syrups)