Right after the root procedure you will noticed that the phone will show:
kernel is not seandroid enforcing on top left of the screen for some seconds.
This is just the bootloader recognizing your phone have root and letting you know.
This message is normal and is shown on all Samsung phones that use a root enabled kernel.
After the unlock if you wish to un-root you may simply flash the stock rom and that message won't be displayed anymore, you won't lose data and unlock won't be affected by the un-rooting.