Hi sofiene and welcome to the RevPi Community. If you make a copy of the image and write it to another device all settings will be equal.
The MAC address, the PiCtory configuration, the password will be the same.
So here is my recommendation for you how to provide a factory reset after "cloning" the devices:
1 - Reset the password i.e. to "raspberry" before you make an image. You can use the "passwd" command
2 - Delete the file "/home/pi/.revpi-factory-reset"
3 - Make the image
4 - Copy the image to a device
5 - Boot the device with a HDMI monitor - you will see the IP address at the end
6 - Now you can do this manually or with the attached Python script
a) you login and you will be prompted for entering device type, serial and mac address. You find the values on the front of the device.
b) you run the the attached Python script from a device in the same network.
You have to type in the IP address that you see on the HDMI monitor and use a barcode scanner to scan the two QR codes on the front.
7 - After a reboot the MAC address and the password are factory-default as on the sticker.
I wrote this script just for making my life easier. So I'll post it here without warranty and with all the uglyness
Useful tips are welcome.
Have a look at the comments "install SSH key" or "don't install SSH key" (yes it is a bit quick and dirty).
Here you may provide a SSH key for authentication so that you don't have to login using a password.