I'm 39. read there are rare instances where someone my age can grow couple inches taller. is it true & what would make it happen? aren't bones fused?

False: : Unfortunately at 39, you can only appear taller through better posture and wearing shoes that create more distance between the bottom of your feet and the ground beneath them. Even if you were using growth hormone, it would be necessary to do that before the bones epiphysial plates closed (e.g. during adolescence) to gain height. So work on your posture and don't forget calcium and vit D.

Never heard of that: I am not aware of those instances. You're right in that growth plates are closed and no new bone is being formed in those areas. The only other exception for new bone formation is when one has a fracture but that process is different from lengthening the bone. Plus, why would you like grown any taller now? I am sure you have so many other traits to be admired for besides your height!