Are these some kind of varients? New pic added 7/14

[LadyMoondancer]

IMO the farther-away Sky Rocket is discolored--I once bought a complete set of Sparkle ponies from someone and they had ALL yellowed (especially Star Hopper).   

On the other hand, all the Moonstones I've come across in person have been powder blue, not that more "baby blue" like the righthand Moonstone, so I think there is something going on there.

[hathorcat]

I had no idea that rainbow ponies were also mail order.  I knew the collector ponies were mail order of the first 8 ponies and then some of the more commonly known mail order ponies after.  Thanks for the info!

No problem - not all the Rainbows got mail order releases just Confetti, Trickles, Pinwheel, Moonstone, Flutterbye and Parasol. Parasol and Confetti were offered with terrifying regularity throughout the mail order process

[Elisto]

On the other hand, all the Moonstones I've come across in person have been powder blue, not that more "baby blue" like the righthand Moonstone, so I think there is something going on there.

No, mine really are two slightly different colors. I was surprised to see that difference myself, but it really is there, and matches the symbol difference like the ones FairyDust posted. Also, the one with the larger symbols/lighter body has slightly darker eyes, although I know eye color does vary slightly in general, so that may be nothing.

[LadyMoondancer]

Oh, I didn't mean to imply that one Moonstone was discolored.  I've never seen anything discolor from powder blue to a baby blue.  What I meant by "something going on there" was some kind of release variant.