If, in the Displace modifier, (as you could with any other modifier) you click the little mesh-triangle tool-tipped 'Adjust edit cage to modifier result', you should be able to edit the vertices, and see the normals, of the modified mesh.

If, in the Displace modifier, (as you could with most other modifiers) you click the little mesh-triangle tool-tipped 'Adjust edit cage to modifier result', you should be able to edit the vertices, and see the normals, of the modified mesh.