I'm not buying into the generic vs. NPC argument. Just how many gargantuan dragons are their running around in your adventures? Any dragon that has been around long enough to grow to gargantuan size is going to have acquired some magic and is going want to employ it. Cadrilkasta is a better representation of what a party would encounter than anything that has been made before. Quite frankly, I think that even huges and larges would have some items on them. Does it look a bit odd? Well, maybe it takes a little getting used to. But does it fit how Pathfinder and D&D portray dragons? Absolutely!
I think people have varying levels of suspension of disbelief and often prefer to 'imagine' the additional details to a D&D/Pathfinder miniature rather than to have it already on display. I for one don't mind the bling this dragon has got, and it certaintly fits the monster's background but I must confess I do have an issue with the etched runes on it's underbelly. That alone for me says 'individual NPC' rather than 'generic gargantuan blue dragon'.