Depends on what you mean by “configuration file”. There are two flavors of those- system backup and configuration export. You should always use export to move configuration from one device to another. System backup is primarily meant to be restored on exactly the same device it was made on. It may be used to move configuration to another device of exactly the same model with some caution (beware of MAC address cloning), but will most certainly cause troubles when applying to a device of different model. More info here.
Yep, you’ve got it right.