Most likely they're all saums

Gold saums would be the ones with the orange tail...the white tailed ones are sometimes called white/silver saums. Technically, they are NOT Green Terrors.....but petstores still call them that so everyone still calls them Green Terrors. Gold Saum would be the more legit name for them.
The name "Green Terror" came from the original Aequidens Rivulatus that is really a mean fish. It dissappeared from the hobby some 15-20 years ago. I think the reason is, in the fish market, dealers would rather grab the Gold Saums which are easier to get from Ecuador, Guyana etc., they look more attractive to buyers, and are less aggressive making them compatible in consumer's fish tanks....as opposed to the Real GT which are harder to get a hold of, they live in a kinda hostile area of Peru, are less attractive and meaner.
I haven't seen any Real Green Terrors for sale. Only Jeff Rapps online.