You're approaching this from the assumption that the story of their release date is true. Let us take a look at why we should not approach it from that perspective:
1. At this juncture there are no known entities who have stepped forward and provided any reasonable claim that Bytecoin existed prior to March, 2014. I'm not talking about purchased accounts on Bitcointalk, I'm talking about individuals who have a reputation they can stake on such a claim.
2. At the very least, one would expect (were their "deep web" release claims to be true) that there would be darknet market operators who would have been approached by users in the early days. It is inconceivable that with their claims of "mining teams", claimed usage on Tor sites, and many alleged users, that not a single one bothered to say "hey I wonder if the Silk Road will be interested in this untraceable and unlinkable cryptocurrency". By the time Bytecoin allegedly launched in July 2012, the Silk Road was very well known (at least since
Gawker's article in June of 2011, and even before that
when it was mentioned by altoid on Bitcointalk in January of 2011). The original Silk Road forums (the
complete contents of which can be found in the StExo backup or searched via
The Hub on Tor) contain absolutely no mention of Bytecoin.
3. In deference to the previous poster's claim, a search of 4chandata.org, 4chanarchive.net, or any other 4chan archive site unsurprisingly reveals no mention of Bytecoin.
As to whether or not they've dumped their premine, given the unbelievably low Bytecoin exchange volume I simply think they haven't been able to. In order to dump a premine you have to have buyers, otherwise who are you selling it to? Leaving aside HitBTC, which is known to be untrustworthy and filled with fake trades (
1 2 3), Bytecoin does about
$2/day in volume. The most heavily traded day was June 21 when they did around 1.5 BTC in volume at a price of around 10 satoshi per Bytecoin. In the 245 days it has been listed on Poloniex,
even if they were at peak every single day they would only have been able to dump 3 675 000 000 Bytecoins of their stash of
147 882 114 539 Bytecoins, which is 2.49%. Given that they're not at peak, the best they could have achieved over the past 245 days is a couple of hundred USD.
Edit: forgot to add, the only coin "rankings" worth looking at are
CoinGecko. If you're merely looking at market capitalisation then you also need to use
CoinMarketCap's non-mineable/premine filter, but frankly there's not much value in market capitalisation metrics without taking other things into account (eg. market momentum, trade volume, etc.)