Instrument case with stickers?

Well me and my boyfriend's 6 month aniversary is coming up and im
going nuts trying to think of a present for him. Since he recently
bought and started playing the ukelele, i thought id get him a case
cuz right now he doesnt have one. these are the two cases im looking
at:

http://www.guitarcenter.com/Gator-GC-Uke-Deluxe-ABS-Soprano-Ukulele-Case-104387535-i1167531.gc#

http://www.guitarcenter.com/Musician-s-Gear-Soprano-Ukulele-Case-712791-i1522506.gc

(im planning on going to guitar center and making sure these are the
right size so thats not what im concerned about.)

what i want to do is kinda personalize the outside of the case with
stickers and stuff like that but i wasnt sure about these two. would
it be ok to do that with either of these cases? like considering the
covering on the outside of them?
any help is apreciated. 10 pts best answer!