I saw a short interview of Star Trek’s prop director. He said their primary source of props was Paramount’s dumpsters. There was one scene in which he pointed out that the design on a wall was in fact plastic coasters.
They did have one advantage. No one really knew what a star ship should look like.
Years ago back in public TV land, we had a show called “What In The World Is It?”
People brought in oddball and unusual antiques and oddities. The resident experts had to work out what it was or at least come close if possible.
One time a guy had some of the original TOS props. He had the communicators, little phaser, and maybe the bigger one.
The communicator dials according to him were off Matchbox cars.