Just so I completely understand the question... You already have, installed, the server instance of "Microsoft Configuration Manager", Current Branch. (for example, on a Server, you have "Microsoft Configuration Manager Primary Site Setup", version 5.00.9106.1000 (as an example, it may not be that exact version); AND you have clients reporting to that site, and those clients are happily doing ConfigMgr things.
Now, all you want to know is, whether or not, since you have a fully licensed and working CM environment, if elsewhere in that environment (on a different workstation, or a server located across the country, but those devices are joined to the same domain as the server which is the primary site server), whether or not you can take from <installed location on the server>\tools\ConsoleSetup, and run the consolesetup from that set of files, and install it on <some other workstation or server>, and when it prompts post-install, you can put in <your CM server.fully.qualified.domain.name>, and THAT ONE COMPONENT, the admin console, that does or does not need an additional license?
For that specific thing, presuming you have licenses for CM itself, the clients and the server install are all licensed... then NO, you do not need "more" or "different" licenses to install the admin console in multiple places.
That said... I personally would NOT install the admin console all over the place. The reason why I would NOT do that is because the console connects via the WMI Provider (which is usually co-located with your primary site server, unless you've done something very deliberate to move it elsewhere), and that connectivity "could be" slow across your network.
If your end goal is to make it so that people who need to use the Admin Console don't just log right into the Primary Site Server to run the admin console, I suggest installing the admin console on something like a Terminal Server, or an RDS server, or a Citrix Server, or a virtual workstation, which happens to be as close as possible (network-wise) to your primary site server, and have people login to THAT.