I've been given a few promo codes here and there, and I can't find any rhyme or reason as to whether or not I subsequently can rate and/or review the game in iTunes. Sometimes I can do both, even weeks later. Sometimes I can't do either, no matter when I check. Are there promo codes that allow rating and reviewing, and those that don't? Or is it on an app by app basis? Or is there some rule of thumb or guidelines to follow? I've gotten PM's from a few devs wondering why I haven't rated their app, but in those cases the answer was I simply couldn't -- iTunes wouldn't let me! It says, "To rate this app, you must own it", and even though "downloaded" is clearly there, not buy, I can't do a thing. Yet other times this isn't a problem. Ah, the mysteries of the iTunes store!
Well, in my experience with promo codes--when redeeming them on my iPod, I can't rate them, but I can with iTunes on the computer.