Find original sales information of MacBook by serial number
In addition to Max Ried's answer, several more sites share EveryMac.com's functionality, including the following:


PowerBookMedic
Apple Serial Number Info
http://www.chipmunk.nl/klantenservice/applemodel.html (English translation is on the site)
Apple support website (this is really a search for tech specs, and I think you've already mentioned it in your question,  but you can also search by serial numbers here)