This is a very puzzling topic. Within the rebuild video and other documentation it is a part of the procedure to label parts when taking them apart. For instance, the front/rear rotor housing, the front/rear rotors, the apex/side/corner seals to their relative rotor and each other.
My question is this, I can understand if you are re-using old parts, but if I'm using new housing (front and rear have the same p/n) and new seals front and rear should make no difference. Same goes for rotors.

Does anyone know for certain if there are any reasons why the relative locations must be followed.

 

It's a good idea to put the parts back where they came from, but if you're using new parts, it's no biggie. I think there is a minor difference between front and rear rotor housings (mainly EGR passages, I believe) but they're marked F and R from the factory. BTW, I re-read your post - that may be an FC thing, I've only built FC motors so far .

Rotors, it's a good idea to keep track of what seals went in what slot on what rotor if you're re-using seals.

Dale

 

If you dont put the rotor back in the same position, the rotor bearing will be spinning in a different direction than before. As the rotor turns, the apex seals are constantly leaning against one side of the apex seal groove. If you put the rotors in the wrong place the apex seals will be leaning on the other side, so the rotors will start to form a "V".

If yo look at the corner seals, thers only wear on one side from the side seals. Same idea as the rotors. If you put the corner seals in the wrong place, you will end up with more of a gap than what you can measure.

All the parts are label so that if you were to reuse everything you can put everything back in the same place so the clearances stay the same.

But if you are using all new parts then there is nothing to keep track off.