"Our archives and information all point towards these pieces being the ones that were missing for over six centuries. None of the experts we consulted have doubts about this," he added.
Studies have shown that they were printed around 1840 in St. Petersburg. Roloff estimates that they are collectively worth about 250,000 euros ($321,300).
According to Berlin's Humboldt University, the Soviets plundered more than a million books and thousands of pieces of "Beutekunst", or "looted art" at the end of the World War Two. Many pieces have still not been traced down.
The prints, which Roloff said were submitted to Sotheby's by a private German art lover, were pulled out of the collection and are being kept in a high security room in London, the auction house told German daily Die Welt.
Roloff said that it had not been decided what will happen to the pieces now.
"The most elegant solution would be to bring them back to Mecklenburg," he said.
(Reporting by Josie Cox, editing by Paul Casciato)