Newbie AR Question

[odourboy]

I've noticed that in some photos of watches with AR coating, there's a purple-blue hue to the crystal when reflected in the light at certain angles. I was wondering if that's an indication of a coated crystal? I recently received a Tag Carrera rep which, although it was not advertised as having AR coating, it also has this hue. Here's a pic - you can see a purplish glow on the left side of the dial. What do you think? Is that a coated crystal (or just an uber cheap one)?