There are two A1342 machines, the 2.26 Late 2009 and the 2.4 Mid 2010. I don't see any problem with the swap except make sure you get the A1342 board. There are other 2.4 boards that may not work.
http://www.everymac.com/ultimate-mac-lookup/?search_keywords=a1342
http://www.everymac.com/systems/apple/macbook/specs/macbook-core-2-duo-2.4-white-13-polycarbonate-unibody-mid-2010-specs.html