Are they connecting to ePO or an Agent Handler in the DMZ?
If AH then no (Epic Fail on Architecture by McAfee - they are working on it).
If ePO, still perhaps no because of NATing.
Is ePO exposed to the WWW or are they hitting through a VPN client?
If the VPN client is NATing then no, if it is something like netmotion then it will.
The question that you will be asked: Can ePO ping the device when it is connected. If it can it should update, if it can't ping then not a chance.
Is ePO reporting an internal IP? Most people will have the firewall on the client PC turned on, meaning if you are using home router, or broadband then the firewall will turn off unsolicated inbound connections, therefore ePO wont get to the client.