I'm gonna go with the rest and say that at first look it appears more like mold from the picture. When the mold is really white, it's tough to tell, but that stuff looks almost green! And I agree that these have not been out long enough to look like that. I have a couple La Riquezas from shortly after release, and they have just the beginning of plume (meaning a "twinkle" when you look at them in the sun, but nothing to the naked eye).
And do NOT give your B&M the benefit of the doubt. The employees are probably taught to say that it's plume no mo matter what (and might themselves not know the difference). My B&M has sticks in the cases that they must think have plume, but to me it really looks like mold. Even online customer service reps are told to always tell customers it's plume and not mold (even CI does this).
But if it were me, not only would I take them back but I'd make big deal out of the fact that they LIED to me and told me it was plume when it's mold that could literally make me SICK. It pisses me off when someone tries to screw me over ... or in this case one of my friends :argue:
If you want, I'll go down there and make him an offer he can't refuse ...