Cream Dreams

I recently started taking milk deliveries, partly to help dairy farmers get a reasonable price for their product, partly through a kind of 1970s Unigate nostalgia. It works well enough, but my milkman (unlike my mother's) delivers milk in plastic cartons, not recyclable bottles, and there's half the point gone right there.

Does anyone in these homogenized days say "Top of the milk"? It was a phrase much in use when I was young, and milk had a top - but now the cream does not rise, although through long habit I still find myself upending any new bottle or carton to mix it up.

I've always assumed, by the way, that this is where the phrase "Top of the morning" came from. Is that true?