No you're not!
If you download the
NBA 2K13 Roster Editor v0.23.0.1 from
here and open your MyCareer Save File, find your MyPlayer (this might be hard to do because there are so many players in it, but if you look by the team number, your player should have the same team number except he won't be with your teammates, he'll be by the bottom). Then if you scroll across, you will find that you can change your shoe brand and the code for your shoe. If you want a Spalding shoe then you change from Nike or Jordan to Spalding and type in the shoe code. The list of shoe codes you can find
here 