According to the people over at Beckett, if you submit a card for grading that has already been through a Raw Card Review, it will not receive a lower grade unless it has been physically altered or removed from its protective case or if there is clear evidence it has been tampered with. It could receive a higher grade depending on the service level of grading (BGS, BVG, or BCCG). Most cards submitted, however, will be reslabbed in the standard grading case, serial numbered, and labeled with the same grade as the RCR. I haven't had first hand experience with this so I am just going off of what they attest to (and we all know how well that works sometimes).
Hope this helps.