Actually that was rather too brief a response.
Make sure that the you get a licence, yes, but also make sure that it is
transferable and that you have all the original supporting media and
documentation. I must admit to not knowing the complete terms but if you are
buying a version which requires activation you must make sure you will be
able to activate it - you shouldn't have a problem if everything is above
board but if there are any doubts in your mind, steer clear.