From someone who uses the G4 and G5s for scanning. There's some stuff that can be imported and exported. That might help save some typing if you have a lot of talkgroups and frequencies for systems. It doesn't help with zones and alerting information.
Another option that may help your situation, if you're like me, and using both G4s and G5s, is using the G5 as the "master" for doing additions, updates, deletions, etc., then convert that profile to the G4, any VHF or UHF stuff that is in the G5 profile will be defaulted to a 700Mhz frequency. Obviously, the VHF and UHF stuff would not work in the G4, but it saves me having to update multiple code plugs.