I measured the rpm on one of my tower 46's with a MAS 10-6 and it was turning 14,400

Regarding the I-R device, the blue anodize of the head may be throwing off the emissivity of the aluminum head?

If the engine runs good there is nothing wrong with it. I can tell if they are hot by the smell and looking at them when they quit. I don't use the I-R gun