Ok so in the end we created backups and then installed the new policy. Everything works and I haven't noticed anything.
Today I tested and found out that on R80.40 if you open Gateway Cluster Properties -> Network Management -> double click network interface -> click "Ok" while changing nothing -> click "Ok" in Gateway Cluster Properties window.
The smart console freezes for a while then the properties window closes then it freezes again.
In that moment I see 3 changes in session. When install them I see in audit log
The change : "@Interface Index: '1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15', '16', '17', '18', '19', '20', '21', '22', '23', '24', '25', '26'...."
Which I presume is automatic Index updates which would happen if I were to change an interface (though I didn't)
I have tried few other things but I always generate some kind of update for given box or cluster I can see some audit logs.