Engine rotors can only go front or back depending on scallop right ?
 

I am not able to find many posts here regarding engine rotor position

I had a small debate between 2 engine builders as to what helps determine rotor position.

Mazdatrix seems to confirm what one of them thinks and that is that the cut out next to the apex seal will be on the right for a front rotor and on the left for a rear.

https://mazdatrix.com/product/rotor-13b-04-on-front/

The info that Mazdatrix has on their site is correct.