Struts can be rebuilt by specialty restoration houses. See https://www.gazshocks.com/gaz-classic-rebuild-service/ as an example. They can thread your strut's top tube, so that ride height is adjustable, and can even upgrade your struts to adjustable damping. I'd appreciate the damping, in particular. My Reatta rides like, well, a Buick... A little more tautness and responsiveness in the suspension would make me happy.
I'm sure this service isn't cheap, but since this thread is about where to find non-existent rear struts, maybe it's time to take a different approach.