Didn't take long.
The most important thing I needed to figure out, was which way the extra cones in reptiles eyes work. Do they let them see higher up into the spectrum, or lower.
It turns out it allows them to see higher up into the spectrum.
I can't find anything about pure IR. All I can find is Near-infrared, or NIR. NIR is just barely past the human spectrum. MWIR is also just barely outside of human eye capacity.
Now, I can't find any sources explicitly stating the how high (or Low) of a wavelength a bearded dragon can see, but it's safe to assume that with their better vision, they can easily see a light source just barely out of our visions capacity.
-Brandon