I doubt any exchanges were involved in Silk Road assets. The advantage of VCs is that you can make transactions between individuals without any bank or exchange involved. Silk Road held their assets in their own wallet. When busted by the FBI, it took that agency several days to access the wallet information.
Besides, it was the bust of Silk Road which proceeded the huge rise in BC values, IIRC. The loss at MtGox was likely the result of something called "forking", the duplication of internal wallets of clients. Once the wallets existed in duality, the controlling entity of the cloned wallet was able to move the funds to other locations. It's like keeping two sets of books, one for the IRS and one for your records.
