This evening, we had friends over for pizza. The boys all played very nicely and when they were getting ready to leave, Wil told their son, "Thank you for playing cars." Unprompted.
A week or so ago, Sam wanted to play cars with Wil. Wil has several Lightening McQueens so I asked if he would let Sam have one. He did. The next day, when cleaning up his cars, I put that McQueen in Wil's bucket. He saw and corrected me, putting it in Sam's and telling me it was Sam's car. He really can share!
I know there are others, but those are ones I can remember. Despite all the fights over toys, I have hope that he is learning some good manners.