We have been towing our polished '65 Caravel
for over ten years, much of that in California. No problem.
You can hardly go down the highway without coming across a polished tanker truck.
The biggest problem with a polished Airstream is, if the inside of the door is polished, having the sun reflect off the concave surface when the door is open and burn your patio rug. I thought it was not possible until it happened to us.