How do I identify my Macbook Pro without turning it on?

I recently bought an older model Macbook Pro from a surplus sale at my school. It has no battery, and when I use the charger cord, it won't turn on. (My Macbook A1181 will power on this way, so I assume the Macbook Pro will too.) Other than going into "About This Mac" and doing it that way, how do I figure out what model Macbook Pro I have in order to go about fixing it?

Thank you.