I'm going to say that's probably a hard no. If you're not cleared then certain documents will just not exist or would come back saying that some information has been redacted for national security reasons. You can see some examples of such requests here if you search hard enough https://www.muckrock.com

Looking at their website they have GDPR forms for employees and for clients, but they don't have anything for Joe Public, not sure if this is because they don't 'own' the data themselves?