So there really is no way to tell unless you get her mib/mip? If the comb/brush is the only difference. I have lemondrop and peachy with only front hooves stamped. Or are you saying that the slight color difference of the pony is how you tell? My little wiki said that there are 45+ variants of blossom.
Unless you have the later MO, it seems. She really is a different color! From what FF is saying, #s 2-4 *should* be the same color, the differences in them are due to yellowing. I think the 45+ variants of Blossom include all her nirvana variants.
3 colours of Blossom total for the US line.
1 and 2 should match in shade (colour one)
3 and 4 should match in shade (the offers placed in front of #4 are where that pony is ordered from) (colour two)
5 is unique, and I placed the offers I believe she could have been ordered from in front of her.
(colour three)
(1&2group 3&4 group) the ones who should match up in shade I intentionally used my "best" example as well as a more yellowed example I owned still. Just to show what can happen with heat/light/play (oils from hands).
Ignore the eyes. purple paint is VERY photosensitive (red pigment) so from UV or heat the red can fade away leaving purple eyes lighter, or even turning a periwinkle shade. even ponies from the exact same issue and set- purple paint can have batch varations as well, or slight changes to liner colour for the same reason. I hope this all helps.