Yea, PetSmart's "Dragonscale Bettas" are more accurately considered plakat males (there was one that I thought may have been female, but upon closer inspection was definitely a male). Oftentimes they are dragonscales as well, but not always, and we've had some dragonscale halfmoons come in that were labeled as halfmoons.
Dragonscale isn't simply a metallic fish, but the scales are supposed to be thicker as well (easiest to tell on the gill plates) -- much like a dragon's scales are supposed to be thick. Color-wise a "true dragon" is supposed to have a white dragonscales on the body overtop of the base color, which shows in the fins. Apparently there has yet to be a "true dragon" with the blues -- they can have the thicker scales, but they won't have the white scales on the body.
Here's an article on dragonscales: http://www.bettaterritory.nl/BT-AABDragons.htm
It's a bit of a read, but I found it to be rather interesting myself.