my first concern was they may try and dump them today. on smaller exchanges or trade into alts, then sell.
or they could just secure in multiple wallets and leave for years. then sell when everyone has 'forgot'
maybe a dump is on way today or they may sell on localbitcoins slowly, who knows
I highly doubt they would dump them on an exchange -- what exchange allows fiat withdrawal without KYC? Are there any exchanges that even allow P2P transfer? Maybe BTC-E codes, haven't been on there in a while.... anyway, if it were me, I'd mix them, then slowly sell them on LBC. And keep a fat stash in cold storage too.....