Gearbox mechanism go look see seems OK to me - but what do I know.. Grey ball has about 3mm movement in the housing and measures between 16.91 and 17.15mm at the max section. Is this normal or is it worn? Other than that seems OK wear marks on the selector (3rd picture down)
Ball should have no discernible movement and yours does looks very worn, the outside rim is quite thick to start.
The rest looks ok, the other weakness is the bracket holding the doodat with the spring which, when it does, breaks across one of it's fixing screw holes. Show us inside the nosecone please.
If you think of the gearstick movement at the front, 3mm at the rear in the gearbox is probably about 50mm at the top of the gearstick. That means all your gear changes will be mushed together. Mine was really bad.. old on left, newer (about 5 years old now !) on right. My gear changes worked by metal-on metal contact with the ball worn that badly..
the metal ones from Heritage require you to expand the hole fractionally to make it engage on the hockey stick properly. I did mine with some sandpaper after bright sparks on here made me see the light. took about an hour I think