yes, you can simply download the latest verion of sep client from fileconnect and install it directly on that win 2012 client. If needed you can simply import the sylink file from your existing SEPM to make it managed.
Note: Though it is supported to have lower version of SEPM supporting higher version of SEP client. it is recommended to install/upgrade your SEPM as that of your client version, so that all the newer features are supported.