Jim -
Thanks so much for your responses, and thanks to the others who responded, too! It all really helped!
Specifically, the date difference you & others pointed out out triggered memories that I suspect explain the number difference on that 1/2" ratchet!
For decades (and certainly from the 1990s to the present) my younger brother & I have worked on our cars together. Unlike me, he actually worked for a while as a diesel truck mechanic for GM &, as a result, he has probably 10x the number of hand tools that I have, including a lot of Craftsman. I've never "lost" or replaced my 1/2" ratchet, but it's certainly possible that I mixed it up with one of his. So I'm guessing that, on one of those occasions, my 1/2" Craftsman ratchet got mixed up with one of his when we were putting up tools.
So I called him this morning & asked about it. At first, he said he didn't think that could be correct, because he hasn't bought any Craftsman hand tools since probably the 1980s. BUT, as we talked more, he changed his mind and said it actually IS a possibility. He said that he has several Craftsman 1/2" ratchets and that, while he hasn't BOUGHT any Craftsman since the 1980s, he has REPLACED several of their ratchets over the years. He said that, whenever a Craftsman ratchet got sluggish or otherwise didn't seem to work as he thought it should, he just took it to Sears & they always exchanged it for a new one off the shelf. He remembers that happening into the 1990s & 2000s, so it's certainly possible that one of those replacement ratchets got mixed up with mine when we worked together!
He recently moved, so a lot of his tools are still inaccessible in boxes in his new garage, but he's going to 'dig around' those boxes & try to find his Craftsman ratchets & report back to me. When I hear back, I'll repost to let you know.
You probably already knew this, but I didn't until I was examining the contents of my set: almost every item in the set has a "Model#" stamped on it! The plastic case, every socket, extension & adapter has a stamped 5 digit number on it. And most are sequential by socket size! I believe only the "screwdriver"-type 1/4" bit driver & 7 included bits don't have model numbers.
Do you happen to know whether the socket numbers also changed over time, or have they remained the same through the?
Paul