Hey,
No, its more than just the 1/4 light bit
For a start there are early and late Oval doors and there are differences between them too.
One of the things I can think of is the way the felt channel fits on a Split door - on the oval, you have the standard felt channel that is held in place with 'u' clips. On the split door, the felt is like part of the metal frame work and is fixed differently into the door.
Visibly I can't think of anything major from the outside that would be different from an early Oval door.
Is frequently found with a glass of wine in one hand and a vintage vw part in the other