VNC console support for hosts which were not provisioned by Foreman

Does Foreman supports VNC console access for the hosts which were NOT provisioned by Foreman? I have hosts in Foreman which were mainly added by ansible-foreman callback plugin, they were provisioned by foreman.

Can I use libvirt or oVirt in order to connect to VNC Server running on those hosts?

Foreman and Proxy versions:
Latest Foreman 3.8