Hmmm...
The bars on the spin bike are shaped somewhat like aerobars.
However, when I was taught to teach indoor cycling.....we were told that getting into an aero position was not important in an indoor class because you are not moving and therefore there is no beneift to being in the aero position.
Personally, I think that there is a benefit to being in the aero position indoors only if you are training your body to be more comfortable on aerobars outdoors.
So, I would recommend that you not bend down into the "aero" position. Place your hands lightly just to the sides on the stem.