Wailaikum Assalam
Rating written on the thermostat is the opening temperature of it.
82* means it will start opening after 2 more degrees then 80*. Thermostat takes time to fully open up.
Engine's temperature will also stay above then 82* while cruising, which should be above then 80* or maybe 80*.
In short engine will run 2 degree hotter in all situations.
Oem systems are balanced. .