Good luck. Lets keep our fingers crossed that its a 2012. If its one of those 2011s that have the GPU -problem you might have some studying to do how to fix it.
You can figure out what it is, if the bottom case is original. Look at the serial number and then google "mac serial number lookup". Also, if the EMC number is marked on the bottom case that could tell you roughly something about it.
Here are the A1286 EMC -numbers.
I think I can use the same charger with all my 2010-2012 MBPs. The power output might be different with various MBP chargers but the Magsafe -connector is the same. So, they work. Charger alone can be surprisingly expensive, you can usually get them cheaper with a cheap MPB.