Answer: 

In the scenario described, There are two possibilities.

Servers A, B, and C are discovered
If servers A and B are licensed, they will be listed within a given app stack. Server C is discovered and appears in the assets list, server C will show within the RSG-Out of Scope Services and is visualized.

2. Servers A and B are discovered, not server C

If servers A and B are licensed, they will be listed within a given app stack. Server C is not discovered and does not appear in the assets list, server C will not show within the RSG-Out of Scope Services and be visualized. Communication to Server C will appear in the Connections tab within the Individual Application View.

Note: If you decide to discover and license server C at a later time, it will show in within an application stack and connections will be visualized to servers A and B.