ceramic brake pad question..

[57 3100]

guys,
on my 57 i am running a disc brake conversion that uses 1970-78 camaro rotors, calipers and bearings on my factory spindles.
brakes fine and drives fine, with no pulling at speed and no pulling when braking.
me, always wanting to make sure everything is fine, i took my infrared temp sensor today after getting home from driving and checked both front rotors.
drivers side was about 40 degrees hotter than the passengers side, like 120 vs. 160 degrees, if i remember correctly.
jacked up the front and both wheels spin equally as hard.
i noticed the rotors looked a little blueish, heated, so that caught my attention, but when i looked at my daily drivers, a 2003 s-10 and a 1990 full size k-1500 4x4, both of those trucks also show a blueish tint on the rotors.
i run ceramic pads on all my trucks to keep the brake dust down.

so, do ceramic pads tend to run hotter and can make the rotors look heated, and is a 40 degree temp difference a problem from one rotor to the other ?
i checked the bearings about a year ago, or about 100 miles ago, and everything looked fine.
thanks guys.

leonard