Generally yes. However, once the info is known, if NOK can obtain it by any other means, they might still be able to use it. So, the answer to your question probably depends on whether NOK can get the same info or doc from another legitimate source. Mere knowledge of the contents won't help NOK except in their efforts to obtain it from another source.
As Wiz said, at this point, the fruit of the poison tree evidence will no longer be available to NOK
Got to go.
IMO Ghors