yes thats correct
now client , will use SEPM for liveupdate, GUP for liveudpate, and they have schedule for liveupdate too.
If you want your clients to use GUP ---------------> then you need to check Management server too
If you want to have Liveupdate internet -----------> then you need to check use symantec liveupdate.
By this you checked all the three options, they wont miss a definitions for sure