What a load of crap.
The 747 wing design was "certified" decades before these winglets were added. As stated earlier in the thread, the winglets serve no purpose other than to squeeze a few extra nautical miles per pound of fuel out of the aircraft. They have nothing to do with lift and nothing to do with control.
These winglets are about as important to the 747 as a spoiler is to a Honda Accord.
Of course it will fly without wingtips. The point is that the design has never been certified with one wingtip.
The right thing to do is to fly the bird back to the repair facility without passengers. The Experimental classification in the United States prohibits the use of the aircraft for carrying paying passengers. Common sense dictates that the same general rule should apply here.