I am posting this here in case it will be useful to someone.
The App Center does not provide Apache Guacamole for UCS 5.2, so I had to set up Guacamole separately; however, I wanted to continue using UCS for authentication and to store connections.
So I have created an extension for UCS which will add Guacamole connections as an object type to the LDAP directory. These connection entries can be read by non-App Center versions of Guacamole.
The extension can be found here on GitHub.