I've seen a few plastic ones, but were just about completely gone with only a few bits of plastic hanging on. Not much demand for this item so doubt they would be reproduced. I'd just paint the pot metal ones to look like the plastic. I know of some military trucks that have been restored but very rare and had some odd parts. One had a huge glove box made of steel.
Seen also outside door handles that were stamped steel vs. pot metal.
Best of luck