How do I tell what firmware?

I am buying a used mpc1000. I have never used one before and was wondering what kind of stuff I should check before paying for it?

Also how do I check the Operating system version?

Thanks.

I am paying 450$ USD . for a black one(i like the blue ones, i think they look cooler but yeah).

Hit the Mode Button and go to the "Other" Screen by Pressing Pad 10.
In the upper Line it tells the Operating system and the Version.

There are some rumors that the black MPC is a bit better than the Blue/Red one (better Pads and a newer Processor) but i don't know if this is is true.