That's correct. But If you are using CSF for example then you can do port forwarding if there are incoming requests to 2086 it will be redirected to 2087.
There are no native features that will allow you to enable the "Require SSL for cPanel Services" option in "WHM >> Tweak Settings" for WHM only, however you could setup a firewall rule to forward requests over port 2086 to 2087, or to block access to port 2086 from remote connections.