Simply having three speakers or arrays of any type does not make a system
LCR. The issue is how well each
channel covers the listener area and how much what the listeners hear may vary and that is a function of the system design, not just the products used. It being MILO arrays does not make it being true LCR any more likely than if it were
Mackie or Behringer boxes other than that it possibly being more likely that the system was properly designed.
Another possibility is that there are many LR + center
mono systems where the
speaker systems are similar to that as for true LCR and the difference is in the related panning and mix bus assignment. Or it could be a cross-matrix LCR system, a sort of LCR on steroids sometimes used for wider or fan shaped rooms. Three arrays could even be an exploded mono system. In the end, you may have to listen to the system and hear what you actually get before making any final decisions.
The main difference between a stereo system and an LCR system is that in a stereo system as you
pan hard left to center you are decreasing the left channel level and increasing the right channel level until both are equal. With LCR you are decreasing the left channel level and increasing the center channel level until it is all center. In a stereo system anything not panned hard left or hard right is going in varying degrees to both the left and right speakers while in an LCR system nothing is ever going to both the left and right speakers. So in a stereo system anything panned center gets the combined coverage of the left and right channel speakers while in an LCR system anything panned center is reproduced purely by the center channel. And in a stereo system something panned midway between right and center is primarily in the right speaker but somewhat in the left while in an LCR system it is primarily in the right and somewhat in the center with nothing in the left. So the
effect of panning with LCR can be quite different for some listeners unless the system is properly designed.