The one on the left is the one I got as a gift for Christmas. I wanted to buy another one for a new project, but I hate waiting around for shipping and a store in my city sells them, so I bought from them. It came in the little official Photon box and everything, so I doubt it's a fake, but it looks very different. The first thing I noticed is that the silkscreen is a darker blue. Then I noticed it has a sticker on the main square metal chip housing, whereas my old one does not have a sticker on that. I also noticed whatever component that is at the top left is soldered a little more "roughly" than usual.
It seems to work perfectly fine, connects with the Particle cloud, updated to the new firmware just fine and everything. I'm just worried that I've bought a sub-par older version of a Photon with hardware differences, or if these are just purely cosmetic differences?