the GWs have only one IP address which is the one connected to the PUBLIC SUBNET of the deployment.
You will be using those IPs to establish SIC. of course they will change when new GWs will be deployed and old will be deleted according to the ASG sizing but we are using the CME component to automatically scan / deploy / delete the ASG GWs from the Management Server.
Check the GWLB admin guide:
https://sc1.checkpoint.com/documents/IaaS/WebAdminGuides/EN/CP_CloudGuard_Network_for_AWS_Gateway_Lo...