I wouldn't rely on the coverstock material as the defacto definition of the ball reaction.  Motiv has had earlier rolling "pearls" and skid/flip solids. 

Terminology like solid/pearl/hybrid unfortunately pigeonhole reaction shapes in bowler's minds when in reality it shouldn't.  I personally trust Motiv's determination of fit of each ball in the lineup and somewhat ignore coverstock type.  It is just marketing.

I agree that we can't set store by solid, pearl, or hybrid. We have even had Newguy, (Phil from radical I think) come right out and say that they can make a solid react that a stereotypical pearl just based on the additives. With that being said, however, I still think we can cautiously set store by those three labels, as long as we also look at the factory finish. The ball manufacturers know bowlers look at solid, pearl, and hybrid and buy based on the stereotypical reactions, so they will tend to make an early and smooth ball a solid because that is what bowlers know. As far as a ball like the tag being skid-flip, it also 5500 LSP, which is why we need to focus more on the factory surface. I'm guessing the tag is a solid for aesthetic reasons. I don't know that I have ever seen an all black pearl ball