Yes and No. If you own RO2 it seems you will also get Rising Storm, but as we found out last night. If you do not own Rising Storm you do not get to unlock the perks of the game. Like new weapons and level up your kits and skills. Cake does not own RS but does own RO2, and was not able to level anything last night while the rest of us who do own RS was able to.
But the game is fun, and I am not sure how much of a edge you get with the whole leveling. I have no unlocked anything new yet.