This is true :)
The Harts are a long-time wrestling family. I can't see them breaking kayfabe on camera. They are way too professional for that.
I wasn't implying they broke kayfabe--I agree the Harts would never do that. It wasn't on-air, but after the match while cameras were following everyone around backstage--I saw it in a documentary later (either Beyond the Mat or one of those documentaries that A&E and some of the other cable stations have been showing recently--would need to dig through my video collection to find it).