Main difference is in the tripletrees. The OCC chopper has rake built in.
The WCC does not.
In other words, the WCC forks are at the same angle as the head tube.
The OCC has additional angle added by the tripleclamp.
There is also a difference in how the bars mount as you can see from the pics. The WCC uses a more modern threadless headset and bar mount, whereas the OCC uses the older style two clamp setup like a motorcycle.
These pics are showing AFTER the swap. The OCC forks are on the WCC frame and vice versa...