There are 9 Exemptions to that Executive Order. These exemptions allow the government to extend the declassification window indefinitely. Number 8 in particular is very broad:
(8) reveal information that would seriously impair current national security emergency preparedness plans or reveal current vulnerabilities of systems, installations, or infrastructures relating to the national security;
I don't think it would apply to this saucer as it is not a "current system" but it basically extends the time limit on any fielded system.
Considering the numerous exemptions including the one for "national security," I wonder how long it extends the time limit on actual government evidence of extraterrestrial UFO's.
I'd imagine that if there were any UFOs and they were classified it would probably be similar to the "born secret" clause that nuclear weapons research gets. So if you discovered anything it would retroactively be classified even if you didn't know it at the time and you could be prosecuted (and worse) for sharing it.
I don't think it would apply to this saucer as it is not a "current system" but it basically extends the time limit on any fielded system.