She's looking good in the pictures. Definitely getting slab-sided but with a slight bulge on the side. But since she's showing some udder development, hopefully she'll take some more time to fill the udder and take you into next month at least. But remember, things can change quite suddenly so since she's close, just keep a good eye on her, and note changes in her personality as she nears her delivery date.
And as to changing color, yes, if you spread the lips of her labia, you will probably see a light pink/salmon color. As she nears delivery, this will darken to more red. As it gets redder she is moving forward to her delivery. That, with the looseness and elongation are good signs of impending delivery, especially if you note changes in her personality. All things work together on trying to guesstimate impending birth.