Back on the subject of surviving Concentration episodes ... Four years ago, a woman made a series of posts here, outlining her successful attempt at locating her dad's 1958 appearance. She found one of his episodes via the Library of Congress, and had to pay NBC for the "personal use" rights to a DVD copy.
You'll find these posts if you search for Britgirl57.
Since NBC has dumped most (or all) of their tapes, I wonder how many episodes the LoC might have?
Sorry, I have no idea of if and where old copies of Concentration reside. I find that woman's story about finding a specific one almost impossible. We went on in August of 1958, which was way before video tape. Kinescopes were available, but requiired special equipment unavaliable to the public. After three months we, the owners and producers could not find a single one. As I've said, when we started using tape, the "brains" at NBC (and elsewhere) kept them for three months, then retaped new shows over them. Unlike sit-coms, our shows were never rerun. They were inexpensive to produce and we tried to keep timely. At that time no one dreamed they could be replayed in syndication. Occasionally, if we had a valid reason, we could order copies of certain shows prior to producing them. But, we couldn't do this too often -- this was costly, no place to store them and no practical use for them. Some of those still exist. Personally, I think most have been found. Yes, Library of Congress has some, how many of which ones, I have no idea.