If you look at the photo NM posted, just forward of the coughpit on the nose, you will see a bit of a bump - that's the in flight refueling point for the probe refueling system that the USAF uses.
I think the USAF has some B747 based E-5 aircraft with a bump where you descibe it behind the coughpit, but I did not think they ever did VIP duties....
Next time I'll take a photo. It was US Defence Secretary Gates. Australia certainly accorded his convoy VIP treatment - there were Police controlling traffic at every intersection and roundabout from the City to the airport. The usual morning peak traffic run of nearly one hour took less than 30 minutes.