Silk Road 2 goes live: did the FBI arrest the wrong Dread Pirate Roberts?

Did the FBI get the wrong man, or at least the wrong Dread Pirate Roberts (DPR), when it shut down the Silk Road darknet marketplace? Claims are being made that this is precisely what happened, and that Ross Ulbricht who was arrested took over as acting DPR from the real Silk Road founder before the FBI made its move. In a statement, reposted to Pastebin today under the title of 'Possible truths behind DPR and Silk Road', someone calling themselves Elthemor Sagewood and claiming to be a well known Silk Road vendor says "In a court hearing today, Ulbricht's lawyer claimed that Ross was, in fact, not the real DPR that the FBI was looking for. This only goes too perfectly with something that was posted on an I2P (Invisible Internet Project) eepsite just after Ulbricht's arrest, and is something I personally have been holding onto, afraid of releasing it into the clearnet for the sake of my strict "what happens in the darknet, stays in the darknet" rule, and how it would affect the case."