I2C is pretty simple, however you need to know the address and registers.
I use it to access RTC chips, and also for MIFARE (although I've not got past the 'oh, it works' stage, as other projects have taken priority over playing with smart cards)

It's usually possible to change the device address (allows multiple similar devices to share the same bus), so I wouldn't be too concerned about it not being as in the spec sheet.

Just read the examples, then dump the read bytes to serial to see what you're getting.
Then figure out what you need to do with those bytes to extract the information you need.