Chosen Solution

I am replacing the logic board on a Macbook Air 2012 13" i7 2Ghz 8 Gb A1466 and was wondering if the gasket between the heat sink and the fan serves any purpose other than theoritical. I have heard repair folks who say they leave these gaskets off. Just wondering what folks here thought.

I don’t believe Apple would go to the expense for theoritical purposes.
Definition of theoretical
1
a : relating to or having the character of theory : abstract
b : confined to theory or speculation often in contrast to practical applications : speculative theoretical physics
2
given to or skilled in theorizing a brilliant theoretical physicist 3
existing only in theory : hypothetical gave as an example a theoretical situation

I think it is to minimise any potential rattle from the fan, and to generally hold it in place. The rubber gasket is pushed down slightly by the bottom cover, which will push against the fan (haven’t got one in front of me at the moment, so this is from memory). If this is missing though, it doesn’t cause any issues, I think Apple were just being extra cautious. Apple do a lot of things which don’t make sense. For example, the taller logic board screw on A1398 models, which is covered by a rubber component, something else which is easy to lose. The hidden logic board screw on A1425 models and the weird change in battery design. Having no standard USB ports in the new MacBook. The list goes on…