If the patch contains good code/documentation, doesn't break anything, works as supposed to do and is relevant to the direction of the project, I can't see why it wouldn't be approved.

If my patch conflicts with the direction of the project, I can just fork.

And no, I never tried because don't have a device running 2.x. I could try contributing to Honeycomb (since I happen to own a Xoom). Is there any repo I could clone containing Honeycomb? (honest question)