No, I think the emails were available the whole time the investigation was going on through a FOIA request for the XKeyScore metadata of Clinton's server. The emails weren't recovered intentionally, as the means to do so were available to any agency that cared to put in the request.
Russia didn't hack the emails, but if they had a system comparable to XKeyScore, or secured the emails though a concurrent investigation of, say, an individual that gained access to the unsecured server, providing the documents to the FBI would not only be legal, it would be their obligation under that treaty.
If they had any of that material, it wouldn't have been an act of espionage, as the server was not secured or property of the state. Trump merely asked them to comply with international treaty law if they were capable of producing any evidence. I hardly call that "treason".