Trek Madone 5.2 headset bearing issue

Bought a 5.2 Frame, fork and headset recently on eBay and starting to put it together. I’ve noticed that when the top headset bearing is placed into the frame there is a tiny amount of movement. This is the. Exaggerated once stem and bars are fitted. Tightening the top cap only stops the forks turning at all. Does this sound like the bearings need replacing? I’d thought the top bearing should be snug in the frame so that tiny bit of movement has me worried. Or could this be something worse? A 9 year old carbon frame, could the bearing seat in the frame have expanded? Any thoughts / help welcome.