'"Apparently it should be possible, sorry for reposting.'"
https://www.ifixit.com/Answers/View/137285/Which+MacBook+Logic+board+should+I+purchase
"The boards are the same within model years... including early to late '11 so if you can find the faster (2.2GHz-2.5GHz) board it would work."
http://www.everymac.com/systems/apple/macbook_pro/specs/macbook-pro-core-i7-2.0-15-early-2011-unibody-thunderbolt-specs.html