http://www.nga.gov/cgi-bin/pdimage?45604+0+gg35a
Lucas Cranach the Elder. Portrait of a Woman 1522
Notice the unusual red plaston. This is evidence towards showing the bodices do not open over a chemise.
Earlier in the evolution of this style, yes, most likely, but by this stage there is a new layer.
On the NGA website, you can zoom in on parts of the image. If you look at the plastron you can also see it has texture. Vertical lines that are shaded to look rounded, could signify boning, whatever it is, it holds it's shape while being forced by the shape of the body underneath.
She is probably also wearing a gollar, which covers the bodice from shoulders to bust.