That's what we do, have the same EAR in Dev,
Test, and Prod. We set up the properties files to be "HOSTNAME.property = property_value", and when we read in the property, we prefix the property we call with the hostname based on the server it's coming from. Since the server name usually incorporates the entire DNS name, we have an additional property that matches the first part of the server name with its hostname and then use that to pass it everywhere. I don't know how pretty that is, but it works well.