I noticed that is seems to matter which one you put where even though they are physically interchangable. I was wondering if there was a visual difference between them if they were to get mixed up? As well if anyone could provide imput to why they would need to be different that would be great. I've noticed the ones on mazdatrix are color coated, does this color coating last long?

 

The taps on them are directional, to make sure the oil control ring doesnt spin.
When installed the downward facing tap should point counter-rotationwise.

Try installing a spring and an o-ringless oil seal - rotate the seal, you will get a better idea of what i mean.

 

the springs are directional the seals themselves are not

 

^ Bingo!