If you have the Key to the Glove Box, don't rekey the glove box lock cylinder - looks like the knob would be damaged while taking it apart.
Rekey the door and trunk lock cylinder and have a keys made. Glove box lock cylinder uses only four of the six cuts on the key starting from the tip of the key. Have the lock smith match the four tumblers of the glove box key starting from the tip and any combination for the last two tumblers - then have a keys made to match the new door and trunk cylinders.
I had this done to my locks years ago. Took awhile to figure it out and explain to the locksmith what I wanted done. Hope this helps.