It seems that there is a lot of confusion about this subject. I researched the Montana Code Annotated (MCA) and regulations about this subject and found this:

MCA 87-6-401 Unlawful use of equipment while hunting

(1) A person may not:

(a) hunt or attempt to hunt any game animal or game bird by the aid or with the use of any snare, except as allowed in 87-3-127 and 87-3-128, set gun, projected artificial light, trap, salt lick, or bait.

I consulted with the local game warden on whether a illuminated reticle was a projected artificial light, and he verified it was not. Of course, spotlights, night vision, laser sights, and IR qualify as projected artificial lights, so they are appropriately prohibited.

If you are thinking the FWP commission can restrict lit reticles through an order as they do electronics on bows, the FWP Commission powers statute (87-1-301) reads:
(7) The commission may not regulate the use or possession of firearms, firearms accessories, or ammunition, including the chemical elements of ammunition used for hunting.

There you go.