Typically when they list the pearl surface as polished, its usually the same surface grit as the solid. So, I would have to say its the same as the Look at a "T" pad (~4000). I wish they would list the surface grit on their pearls. Although there have been some exceptions to this, when in doubt, a quick email to 900 Global will easily clear up any questions.

While my personal, polished, NIB ball surface theory is much in line with KMUMPS's theory (put the finish on the ball you can easily replicate before ever using it),
most polished balls from the San Antonio plant (including old Columbia, AMF, and Track balls) can usually be fairly closely replicated by doing a 500/1000/2000 sanding followed by a medium application of an abrasive polish, like Brunswick's Factory Finish High Gloss polish or Storm's Xtra Shine polish.

I usually find such a finish too skid/flip for many of their balls, depending on the drilling, of course. I much prefer a P1500 or P2000 grit sanding followed by a light spinner polish with a non-abrasive polish like Valentino's Sake Oil.