I don't think that it was Mt Gox. In 2010, Mt Gox wasn't dealing with that much BTCs. Those coins belonged to some other exchange.

There was no "other exchange" before MtGox.

Bitcoin Market was before Mtgox.

https://en.bitcoin.it/wiki/History

Totally missed that one. Was its volume relevant?

Just a 10,000 pizza
There were also people mailing you cash in the mail