The casing is the same on the late 2010 and the 2011 Core i5 model. You should be able to swap them out without too many problems. The heatsink is different on the two models, so you will need to replace it as well.
That being said, you may not want to replace the logic board. With this being a waterspill, the keyboard is probably shot and their could be other damage (LCD connector, solid state drive, daughter board etc). Without seeing the logic board it's hard to tell, but a fried keyboard could make you think the logic board is dead. The power button goes through the keyboard, so you could be looking at something as simple as a bad keyboard.
-- Ryan
iRepair Savannah