I'm too lazy, but if anyone has some spare time, he could do the following: Determine when the auction results were declared to winners. From then on, observe charts for unusually high selling volume, because clever arbitrageurs will hedge immediately. Less clever arbitrageurs will have had to wait until the BTC were sent out, so determine whenever that is/was and look again for unusual volume (after 6 confirmations time minimum).
From the USMS announcement:
On Friday, December 5, by 5:00pm EST, the USMS will notify the winning bidder/bidders that their bid/bids has/have been selected.
The transfer of the coins to the individual bidders (minus the last 2000 BTC block) was registered in the blockchain on 2014-12-08 16:29. (Or is that the date the transaction was issued?)
The Blockchain.info times are UTC, I presume; so the transfer to bidders would have occurred on 11:29am EST. That is ahead of the deadline for bidders to send the payment, which was 2:00pm EST, on Monday. Presumably they all had wired in the money much earlier.
The last 2000 BTC block got transferred on 2014-12-08 19:05 (13:29 EST?).