I don't know if rabbits would like them, but if so, they shouldn't be much difference, nutritionally, from unsprouted sunflower seeds. Lucile Moore's new book says seeds like sunflower & pumpkin are especially good for the giant breeds & to give up to a little more than a tablespoon.
My rabbit loves sunflowers. She eats every bit of it. The wild rabbits do as well. We grow them in the back yard for her but she competes with her wild cousins which is just fine by me.