95 dodge dakota reverse tail light

last week i accidentally hit my friends 95 dodge dakota, and i only messed up their right tail light, and i broke the bottom bulb on it. well i went to get replacement bulbs and the store told me that 2057 were the right kind of bulb for it, but my dad doesn't think that is right, he said he thinks it should only have 1 filament because its the reverse light and it shouldn't have to change color. He wants me to go and say something to the people at the shop i bought it from which i don't want to have to do if i don't have to. unfortunately i don't know much about cars and i was wondering if it should have 1 or 2 filaments? thanks :)

The old bulb has a number stamped on the base. Thats the one you need.