While in a overflow map if you go to the WvW window to see the progress, you see the following message:
WvW information is not visible from dungeons, instances, and overflow maps. Travel to WvW to participate.
Do you still benefit from the WvW bonuses while in the overflow map even though you can't see it? Likewise I I assume it works the same for dungeons and instances so I would like to extend the question to them.