Most weight issues in women with pcos are related to lifestyle, not the pcos itself.
If you keep up a healthy, active lifestyle, and get regular check ups of your hormones, you should be able to catch any unusual weight gain LONG before it becomes a problem.
There's no chance you'll put on 50 pounds overnight.
That said, even though you're a 'thin cyster', you still need to be concerned about visceral fat.
Fat distribution affects PCOS metabolism regardless of body weight