If the coolant level is stable @ the full mark; the temp warms normally and temp gauge rises gradually as it warms you should be fine. My 05 lly was running just above 180 on Friday with temps in the 30s and Sunday with temps in the high 50s it ran around 200.
One simple test to do now and before your warranty goes off is to fill reservoir to the neck and idle the cold engine with the coolant cap off; watch for bubbles in the reservoir. You should Not be seeing any continuous bubbles perking up to the neck. Continuous bubbles would be an indicator that combustion chamber gasses are leaking into the cooling system. After 5 minutes you can suck out the excess coolant or just put the cap on and the excess coolant will go out the overflow.
Not a bad idea also to make sure the radiator core is clean every 80 to 90 thousand miles... cotton wood seeds, pollen, dirt and leaves can get stuck in and on the fins of the radiator. Wash with garden hose spraying from fan side of radiator to front and spray from top of the front downward. Best to pull upper fan shroud and fan too if you can get it off. Have your mechanic friend help or send to a garage (billable time should be about 45min) if you would rather drive your truck than work on it.