System Images with different Model Identifiers I have been tasked with creating a default system image to use to both back up and use to deploy to new systems. 

After checking the stats on the 7 systems in question I've found that there are multiple model identifiers.

Would I be correct in my assumption that a system image made for one model identifier would not be useful for a system with a different identifier?
No, one image should work for all models of Mac that are compatible with that particular version of Mac OS X. A single image can be used across all kinds of Macs: MacBooks, iMacs, Mac minis, Mac Pros.

So check each of your 7 Macs and identify the most recent version of Mac OS X that each Mac can run.