If you want to go to RMC under the Regular Officer Training Program (ROTP) where there is no tuition and you receive a salary, then no, you probably don't want this. Upon completion of a baccalaureate under ROTP (at RMC or otherwise), you will have to serve 3-5 years of obligatory service in your military occupation (which won't be legal officer). At that point (now eight years down the road), you could leave the CF and go to law school and re-join later (many have done this), or you could apply for the Legal Officer Training Plan (LOTP).
If you want to go to law school immediately after finishing RMC, then you probably want to think about the Reserve Entry Training Plan (RETP), where you still go to RMC, but you have to pay tuition and other expenses and you don't receive a salary (except when on summer training). If you graduate from RMC under RETP, there is no obligatory service incurred (although you are encouraged to join the Primary Reserve). I know of at least one current legal officer who went this route. As an aside, I have been led to believe that the salary you will earn during the summers pretty much covers the tuition and other costs you will incur during the school year, but my information is dated.
Finally, if you already have a bachelor's degree, are you sure that four years at RMC is worth the experience?