If you are talking about the teardrop style lights, Airstream Dreams has them. If you are talking about the rectangular Grote lights, Airstream Dreams has an exact replacement, and Inland RV has a knockoff replacement.
With respect to the taillights, you probably have the Bargman 99 lenses (aka, the "tiered wedding cake" style). In 9 months of looking, the only source I've found for a true replacement is Airstream Dreams. Be prepared to wait, however. I was on a wait list for 7 months, and I finally received the lenses last week. They are a very nice quality replacement.
I have noticed that AD removed these lenses from their website, (high demand/long wait list), so you might have to inquire whether they are adding names to the wait list. I understand that they have a new supplier, so hopefully, production will increase to meet the demand.
Inland RV sells 2 types of replacement taillight lenses, neither of which is tiered. One uses regular bulbs, and the other uses LED lights. The LED lights are much brighter than the others.