Last week, BBM's website listed a new set - the 2009 Lions Classic set. This set is a tie-in with the Lions Classic set of games which Yakyu All-Stars describes here. The throwback uniforms this year are from the 1980's.
The new Lions Classic set is a 27 card box set that contains 13 cards of active players wearing the throwback uniforms, 13 cards of OB players from the 1980's and one insert card. There are also randomly inserted autograph cards. I'm a bit confused about the release date - the Google translation says it was released in early June, but since the Classic games didn't start until June 27th, that doesn't sound right. The Babel Fish translation says early August, which makes more sense.
I don't know when the Lions started doing this "Lions Classic" set of games, but I guess this now explains this set from last year - it was the tie-in to last year's set of games with the throwback uniforms being the Nishitetsu Lions uniforms from the 1960's. Perhaps next year they can bring back the hideous Taiheiyo Club Lions uniforms from the 1970's.