Rear wheel collars

[Empiria]

I'm currently changing my old tires for some new road 5's. To put the new tire on I removed the rear axle, including the collars in the wheel. However now I've noticed the collars that go into the wheel actually have different lenghts. Can anyone help me identify which one should be on which side? For example: longer collar on the left side, shorter one on the right?

 

[Oxide]

From the parts diagram it looks like the collar with the flange goes on the chain side & the smooth one on the brake side. Hope the photo helps.