Model number for macs; internal battery test

I was looking to buy parts for an old mac, and I had the serial number but not the model number to get information about it. If he model number hasn’t been scratched off the case, you may be able to read it directly.

If you can’t read or find the model number, just enter your serial here:
http://www.powerbookmedic.com/identify-mac-serial.php

In the end, this was to find out how much an internal backup battery would cost. I then found out that I didn’t need a new one, it was the primary battery that was just too low. Luckily I hadn’t had them order a new backup battery yet. This page shows how to test that:
http://support.apple.com/kb/TA22660?viewlocale=en_US