Head gaskets are not a maintenance item. Unless there is evidence of a failure in the head gaskets, there is no need or benefit to changing them.
A head gaskets failure can include:
a) combustion gases in the coolant
b) coolant in one or more of the cylinders
c) coolant in the oil
For your LIM, I would say if there are no leaks, dont mess with it.
For your "running hot" situation, you need to know what the temperature actually is to make this judgment, a.k.a. "data", the number in Fahrenheit.
Get yourself an IR temp. gun and point at the top of the thermostat housing when the engine is hot, take note of the temp. Then, point the IR temp gun
at the inlet of the water pump, (big hose from the bottom of rad.) take note of the temp., you should have about a forty degree temp difference, (depending on the condition of your rad.) this is with the engine running, in "PARK",
a/c ON. Make sure your coolant is full, and holding proper pressure, and your rad. fans are "ON". The best time to to this is during the hottest part of the day,
this way you can get a good measurement of the efficiency of your cooling system.
Another thing you can do is get a cheap scanner/code reader that will show "live data" when the engine is running, it will show you the temperature the engine
is running at, and you can base your judgment on how "HOT" the engine is running, and then you can look at the gauge on the dash and compare, and take note
of any discrepancy in the two readings. Sometimes the dash gauge is not accurate, and misleading. The "data" the engine receives from the sensors has to be
accurate for the computer (PCM) to make accurate air/fuel ratio calculations.
Knowing the actual temperature in degrees is the most important part, this way when you make a repair you can re-test your cooling system
and compare the "data" from before and after to quantify your repair work, or "go back to the drawing board"!