most bankers will still ask for screenshots of transactions from your email or exchange in those dates, not signing. I say this from exchange requests asking to show where it came from.
I'd tell them screenshots can be faked, and prove nothing. Instead, I'd send them a signed message, printed on paper for their inconvenience.The in Januray 2009 mined coins were transferred in 2011 (txid 567a9a7f9191db644a09985fad113dd6ee770eac69454317430e694305be9c56) with several other very early mined coins. So whoever created that transaction, has the private keys of the other very early addresses too. And some addresses you can find here:
source: http://www.forbes.com/sites/andygreenberg/2014/03/25/satoshi-nakamotos-neighbor-the-bitcoin-ghostwriter-who-wasnt/
Who can explain?
