This is a very good news for audiophiles, given that the LP sets from the original 2006 print cost up to 300$ on various second-hand music marketplaces and that the 180 gram ones are often mixed up with the other, cheaper edition.
Here's the part of the Warner Bros. press release concerning this:
On April 14, 2012, the Red Hot Chili Peppers will be inducted into the Rock & Roll Hall of Fame, and to commemorate this historic event, this classic Deluxe box set of the band's first number one album will be specially priced for Record Store Day. The Deluxe package was mastered for vinyl by Steve Hoffman and includes two 16-page booklets -- "Jupiter" and "Mars." The Red Hot Chili Peppers won four Grammy® Awards for Stadium Arcadium including: Best Rock Album, Best Boxed Or Special Limited Edition Package in addition to Best Rock Song and Best Rock Performance by a Duo or Group for their chart-topping, record-breaking single "Dani California."
This year, Record Store Day is on the 21st of April. They have not updated their website with information above, but one would assume they soon will.