As I look at this more I see that the original PAGS xml file had maven filtering.  I think the regex property value testers is still a better approach than maven filtering the import xml files (sorry for that bad direction earlier Shawn).  It unfortunately means that even if we have a PAGS admin UI in the future, you'd still have to do a build of uPortal to change the property value to pick up the value change.  However in this instance it is not a big deal because the ${mobile.user.agent.regex} is used in spring configuration which would require a new build anyway for it to be consistently applied.