@detox You can do that, yes, but you should perhaps remove the SSH Host Keys or stuff that is -or should be- host specific from the XML.
So I'd recommend making a quick checklist what you have to change (e.g. admin PW should really change on the boxes), then backup, remove one or two things from the XML and use it for bringing those other boxes up and work your checklist to change passwords and stuff while also doing the next box.
We had such a prod-line at some point and it worked quite well. If you prepare a FAT32 USB Stick with the XML file, you can use that one to boot up the other boxes and the config will get loaded while booting when the stick is recognized by the PFI/config loader. So you even save on the "login, restore config, reboot" step.
Cheers