You can apply a primer over a properly prepped surface, even if it's fresh. I wouldn't seal before you prime in this case. Definitely check and see what the primer manufacturer says for what grit it should be sanded with prior to actual application.

Also, 1000 grit is way to fine for reapplying color. You will likely have delamination in huge sheets. 400-600 is as fine as I ever go unless I'm color sanding and buffing.