Aftenposten said "Scream" and "Madonna" are back on the walls of the museum after they were recovered last year, following a daring daytime heist four years ago.
The paintings suffered some damage but have been repaired.
The restoration on "Scream" also revealed the museum's copy was likely painted in 1910, not in 1893 as previously thought, Aftenposten said.
The museum has placed a small question mark next to the new date on the placard near the painting, signifying experts believe it as probable but not certain.
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