Product keys are usually either Retail (ones that comes with copies of windows purchased individually) or OEM. The one you have on the sticker under your laptop is an OEM product key. You are correct in assuming that they use the same image on the laptops that they manufacture. As for the OEM product key, they are basically just a reference that your copy is licensed and not a pirated copy. These are usually pre-activated already. As far as I know these product keys do not work in new installs.
oalee 53 cyberkill(ed) Team Colleague
jingda commented: Nice and detailed information +6
oalee 53 cyberkill(ed) Team Colleague
oalee 53 cyberkill(ed) Team Colleague
~s.o.s~ commented: Welcome back, hoping to make good friends with you. Your friend ~s.o.s~ +7