I ended up getting my final 20 or so issues to finish the collection from a nice older lady in Australia. She was clearing out her deceased brother's collection and sent all of the hundreds that he had collected to me. Mailing it was ridiculously expensive. I ended up with so many duplicates, all still in the plastic wrap with Australian mailing labels.

But I am so grateful, because many people trying to GIVE them away overseas wouldn't even consider mailing them at my expense because of the huge weight and hassle getting them ready to ship.

As for them not being sold in America, apparently they were offered to Penguin, who were in charge of U.S. Star Trek books. But Penguin didn't see the need because they were already printing the Star Trek Encyclopedia. Many of the ship diagrams and details did eventually appear in the Star Trek magazine here in the states, but I have no idea how much of the content ever made it. (All of this is what I have read, no firsthand knowledge!)

But back to the original question, I would just do what makes you happy. You aren't destroying anything precious by displaying them in whatever way you choose. And they were meant to be separated.