OK, right away, "lost" is strong, since we know most of these cigarette-sponsored shows are still in Fremantle's vaults and just never got shown on GSN. Also, nothing would beat actually being able to watch these shows. But...
We've got just about the next best thing over at the I've Got a Secret Website. Thanks to Kevin Segura (a member here) we now have access to notes that were maintained for Gil Fates for each episode for I've Got a Secret, as they took place. The notes are brief (they rarely include the contestant's names, for example) and sometimes hard to read, but with them we've been able to reconstruct just about all of the episodes so you can at least read about the guests and the secrets for that missing year.
Along the way, you'll read about Bill Cullen's wife Carol Ames, the judge who married Marilyn Monroe and Joe DiMaggio, a woman who escaped communist Czechoslovakia in a homemade tank, the self-proclaimed yo-yo champion of the world, and not one, but two different secrets involving Rin Tin Tin. Plus about 150 others.
It's just the calendar year 1954 for now (which is where the notes begin, for some reason) but we'll be going through the entire run and filling in gaps as we can. In the end, we'll have specific details on all but about 30 of the 681 episodes that were produced, something I never thought I'd be able to say. I know this is a passion project to me, but still, I think you might find some of the stories interesting.
https://ivegotasecret.nicepage.io/