There should be three (I think) sets of either one or two tick marks on each cam gear so you can find top dead center easily and properly line everything up.
If the belt is blue, it has been changed to an aftermarket Gates timing belt. If it's black, it will be hard to tell if it has been changed just by looking at it. If you plan on keeping the car for a long period of time and you don't trust the person who owned the car before you, you might want to consider changing it. If you think you might only have it for a short period of time and you trust the previous owner's word that it has been changed, don't worry about it.
07 WRX (Albins 5MT + Blouch 20G)
Jorge Carrillo Tuned (365 whp/340 wtq)