Wow, you really dug up an old thread!
That description sounds like what collectors call a “transition” knife. One blade from one year and one from the next year - happens every year on some knives as the year changes and Case uses up last year's blade inventory. They usually don’t make a lot of them that way but there are some. It’s nothing unique to any particular pattern but only happens on knives that have more than one “master” blade (those are the only blades that have a date code stamped on them). The Congress pattern is another like that.
Ken