Lovely coda, however in response to the questions asked above, I'm afraid that the last line isn't clear.

Did you mean it to say that Sam would wear the necklace again if Dean threw it away again? so that he could give it back to Dean again if he had to?

Other than that, the comment doesn't make sense to me.

However, the rest of the coda is note perfect.........if we could see that as the last moment of the show, it would be the icing on the cake