No accounting for batch, either - Beachcomber is the only pearly sea baby that's the same the world over, so the chances of different shade batches for her float is quite high. (Bear in mind the MOC on my page is from a UK release, I don't have a US release image and so can't guarantee whether the shades are the same).
I know some floats have slightly different stamping on the bottom, too.
This may be one for Hathorcat's accessory knowledge...