No, they are trying to pretend to prove the Steele dossier is true. That's the only play they have left.
Hence, this Cohen-was-in-Prague-as-the-dossier-said ploy. And hence Comey's book tour, whose sole mission is to produce the narrative in which the former FBI Director claims that the salacious stuff about Trump in the dossier is "possible."
If the supposed “evidence” that Cohen travelled to Prague made it into the evidence behind the stasi search warrent, that would be friken huge. Maybe that was leaked, just not published.
Pure conjecture on my part. It does explain why Mclatchy would publish it now, though.