Now we have seen other examples of signatures dated with just "2009", but this actually has the date. Is this authentic? If it is, then the fact he is bringing attention to the date could be significant.
This image was taken from a page on the Yahoo! Japan website:
http://headlines.yahoo.co.jp/hl?a=20100504-00000013-oric-ent.view-000
Update: This autograph will be on exhibit from the 19th for only 5days at Roppongi Tokyo. After that, it will be auctioned in Las Vegas. The autograph was discovered in the US but the source is confidential.