The seat is made in a factory then stuck on a chassis on the floor of the aircraft. There aren't any space differences between any CW seats - even on the older LGW jets compared to the new LGW ones. LGW would probably have both the oldest and newest NNCW seats, so a span of 10 or so years between seats. When NNCW was introduced, there weren't any changes to the seat numbers.

The older version, ironically New Club World, will be remembered here for the blue fans it had between seats, instead of the electric privacy divider screen. Now this took much more width than the current screen since it folded over on itself, so if anything that version had less space. On the other hand it had front facing window seats on one side, so that may have changed perspectives. The last examples of this seating survived some 15 years until quite recently (August 2016), when the last longhaul 767s went out of service on routes such as BWI and GCM.

Because of the chassis, the only real difference is external to the seat itself. So some seats such as 64A have a lot of extra space at the end of the seating area due to the position of the bulkhead and they couldn't get another seat in UD. Also the presence of side bins (747, 380) clearly gives sideways space, whereas at the front of 787-8s the fuselage narrows and takes quite a fair bit of head room when standing. Psychology must also take a part, some people think the 777 dorm has more space, due to the size of the cabin. It hasn't.

So I think the OP's alternative interpretation may be nearer the mark. Crack open the Ryvita.