OK…it’s time. You don’t declassify a document. You reclassify it. Classified documents have cover sheet on them. That sheet states the classification level, the permissions for review, copy restrictions and the secure location in which the document must reside. The fact that you have a secret clearance does NOT allow you to willy nilly poke about secret docs. You must have a “need to know” and be in the permitted group to review.
The president can order a declassification or change in classification of a doc up or down. He can also change the other parameters on the cover sheet. But he does not do so unilaterally. The documents final reclassification is done by the custodians of the document in compliance with the presidents order. After reclassification a new cover sheet is attached.
If Trump just grabbed a box of docs and hauled ass with it the docs inside had their original classifications attached and had not been through a formal declassification review. They still had their original classification.
If any of these looted doc are NRAS or other Nuclear Assurity docs they are definitely still in original class as NO ONE can down grade such a document nor can they be in possession of it unless they’re in the NRAS. A nuclear related doc outside of a highly secure SCIF is a national security hazard. Even when Trump does it.