*To check your balance, you need your Mtgox USER ID, from your first email of registration at MtGox.
For anyone curious, here's how to find your balance. For example, my original account creation Email from Gox looks about like this (with some numbers redacted):
Welcome to Mt.Gox!
Thank you for creating your account with us.
Your login: ZZZZZZZ
In order to enable your account, you need to enter your validation code on the Mt.Gox website.
Your confirmation code: ZZZZZZZZZZZZZZZZ
Alternatively you can click on or copy it into your browser via this url:
https://mtgox.com/signup/validate?ID=00000000-0000-0000-0000-000000000000&Code=ZZZZZZZZZZZZZZZZ
Best regards,
The Mt.Gox Team
info@mtgox.comhttps://mtgox.com/Note the bolded portion above. I've replaced mine with 0's in the above, but yours will have a UUID-looking string of hexadecimal groups of numbers separated by hyphens. Cross-reference this with the "mtgox_balances" file from the leak. Your user ID will match the "User__" column.
I can confirm my BTC balance shown there matches what it was when Gox shut down, so this is recent data and appears to be a legit database dump.