Also found this reply. Which might help you. Enable the global system property and then hides the button with a Client script on the tables where you do not want the buttons to show.

(make sure the Isolate script is set to false for this (that field on client script does not show by default so you might have to add it))

I ended up creating Client Scripts on each table where I wanted to hide those buttons. See below:

https://community.servicenow.com/community?id=community_question&sys_id=614c6a48dbc1a30c5129a851ca961957