Classified or not
Trump is now saying he 'declassified' all the documents before he took 'em home, which is a likely story coming from Trump but is not at all realistically believable. The inventory included Top Secret and SCI documents which are 'sensitive compartmented information'. There ain't no way in hell dozens of that type documents could all meet conditions to warrant declassification.
And of course, declassifying documents requires following a protocol and at this point, there is no evidence protocol was observed and Trump just saying he declassified the documents is nonsensical.
It's also worth mentioning the legal pundits are saying the potential crimes surrounding the documents apply regardless classification status. Neither sitting nor former Presidents have any business taking classified documents for any reason.