is it correct that even if I use cloud-init I have to seal my candidate VM before making it a template?

In that case what is the correct approach to pre-seal a CentOS 7 VM?

Also, for operating system like Fedora >=20 and/or RHEL/CentOS 7 should I unconfigure NetworkManager before sealing them, using classic network service, or what?

Thanks in advance,

Gianluca