I had the same experience when I upgraded to a used 2010 MBP from my Late 2008 13". The palm rest is rougher, but I believe it is because it hasn't been used as heavily as my own. My '08 is silky smooth, but the '10 and even my dad's 09 is noticeably rougher. But I think they are all like that to a degree until it gets worn down over time.
My question is, how old or new is your friends? If it's new and yours is that much rougher, then return it. You might also compare to a display model and see how it feels.