That last bit could be very interesting regarding Trump. I guess the question is how “unlawfully” is defined. Unfortunately may be one of those things like “classified” where its whatever the president says it is.
ETA: Yeah, unfortunately it looks like I was right 
From this link on the presidential records act (PRA):
Instead, the president is responsible for interpreting whether the PRA applies to specific records, which implicates public and congressional access to those records. And unlike the FRA, the PRA grants the president exclusive responsibility for custody of, control of and access to presidential records during his or her presidency. The National Archives has a more active role under the FRA in developing document preservation policies alongside federal agencies.
…
The PRA, in comparison, provides even fewer safeguards against the destruction of records. The law leaves it to the president to “take all such steps as may be necessary” to ensure that presidential records are maintained and preserved. It also grants the president discretion to dispose of records that “no longer have administrative, historical, informational, or evidentiary value.” While a president must ask the advice of the archivist before destroying records, he or she is free to disregard that advice.