The helicopter would be illegal, at least in WA, not sure about MT.
Prohibited Methods Pg. 80
4. Using aircraft: It is illegal to:
Use an aircraft to spot, locate, or
report the location of wildlife for the
purpose of hunting. Hunt big game on the same day you
were airborne for any purpose, except
for a regularly scheduled commercial
flight
MT is a bit less restrictive.
Airplane Spotting
Aircraft may not be used to locate big game animals for the purpose of:
Hunting those animals during the same hunting day after a person has been airborne or;
Providing information for another person for the purpose of hunting those animals within the
same hunting day after being airborne;
The use of unmanned aerial vehicles (UAV) for the purpose of locating, spotting or hunting
big game, upland birds or other species under the management authority of FWP during
commission-established hunting seasons is prohibited.