No, you don't need to.

There is zero-touch enterprise provisioning available, that requires you to be connected to a suitably configured local network (if learns about what it needs from dhcp tags), but this is not something that normal users need to be concerned about. For a non-MDM-managed mac, you can do everything offline just fine. Or you can be online, if you do not want to use iCloud account (I'm not using it either), you can finish the OOBE wizard and everything will be just like the user wants.

I'm pretty sure you don't need a network connection to set up a mac unless this has changed in recent releases.