Correct, the center part of the wheel, the hole in the middle, is larger on the E39. So, without the hub centric rings, they will not fit snug. But this is typically not your biggest problem, the offset is way off, meaning...these wheels could stick out further on your car and you could run into rubbing issues on your fenders.
I made this mistake a couple years ago. My advice, keep looking, you'll find the setup that will work, both mechanically and aesthetically.