That model identifier applies to 2 MacBooks, Late 2009 & Mid 2010.
The former can officially (recognised by Apple) have the RAM upgraded from 2GB to 4GB (unofficially people claim the MacBook will recognise up to 8GB), while the latter can officially have the RAM upgraded from 2GB to 4GB (unofficially from between 8GB (running OS X 10.6) - 16GB (running OS X 10.7.5)