(how many times do I get to say this?)
Depends on which model you have, and the main difference is, you don't usually find out when the MacBook Pro was MADE, but more likely when it was SOLD. The serial number, for example, will tell you when it was manufactured. There's several sites where you can enter the serial number, and the site will respond with the manufactured date, such as here:
http://www.appleserialnumberinfo.com/Desktop/index.php
However, some MacBook Pros are sold as refurbs, and those usually have different serial numbers, which might refer to the refurb date, and not the original manufactured date. So - it's not so easy as just asking which one you have. No one here knows which one you have, until you tell us. "Made in 2008" just isn't enough.
The "seller" should be able to answer your questions, if they know anything about the MacBook Pro. If not - choose a different seller!
bottom line - the ability to install, and run a particular version of OS X is BEST determined by knowing what processor you have, and also knowing the system's model identifier, which is available in the system's hardware profiler.
If you already have that information, you can find out just about anything you want to know by downloading and running the comprehensive "Mactracker" app. You can get that through the App Store, or download directly:
http://mactracker.ca/
You can also get lots of Mac information at a variety of sites - here's one:
http://www.everymac.com/systems/apple/macbook_pro/index-macbookpro.html