Yes, the earlier Tantos had "Made in Japan" printed on the reverse side. I believe that was done from the introduction of the model on through many years of production, so I don't think you can specifically identify which year the knife you're looking at was manufactured. Perhaps if you had a picture of the obverse printing showing fonts used, word arrangement, etc., someone more knowledgeable than I could narrow it down for you. There's a good history of the Tanto model over on the Cold Steel Forums that you might find helpful, too.
I'm afraid I'm not your man when it comes to steels. Back in the 80s and 90s, people weren't quite so obsessive about it. Suffice it to say, if you want to buy the Tanto to use it, it won't fail you. Cold Steel has never used inferior materials.
It sounds like you're eyeing a genuine Tanto. It's one of a handful of knives that forever changed the American knife industry. Please post pictures if you end up buying it. I like seeing photos of those old classics!
-Steve
