Agreed. You have a very nice normal Tokay. The blue headed background color is somewhat common.
Although the background may give rise to a color change in Tokay, so can temperature, time of day or year, level of stress and the presence of a mate.
One of the biggest changes for a newly acclimated Tokay on a good fortified diet is after their first couple of sheds. There can be some dramatic color shifts from the drab wild caught animal of just a few months ago.
Enjoy!