No, that's what Tor is for. They could try to link SR bitcoin addresses back to the point of purchase, though. I suspect they would go after the biggest sellers and buyers, and start with the low hanging fruit -- the people who have unencrypted addresses stored on the server at the time of the bust. I doubt there's much of a distinction between seller and buyer. The top buyers on the site are also sellers, just locally. There are buyers with more purchases than some sellers have sales. Someone buying $10,000 worth of drugs a month would probably be a bigger target than someone with sales totaling a few hundred dollars a month.