I've only got the 2nd & 3rd yearbooks,

, I think there were only 4 published?
From them the format seems to be a stand alone story, a review of the year in the comics story lines (a perfect bluffers guide to G.I.Joe history) & an interview/feature about the upcoming cartoon series...number 3 also has a tedious story about the Dreadnoks cooking for Serpentor (I kid you not!).
Any of the stories which feature the October Guard are entertaining, check out some thier appearances in the Special Missions series, but Triple Play just blows every thing else out of the water thanks to the outstanding artwork.