Verizon FiOS → [Networking] Quantum Gateway Router returning "Not Found" on port 4567

I am aware that Verizon routers use port 4567 for CPE but it seems something changed between the actiontec routers and their new quantum router. Previously with the actiontec routers accessing that port resulted in a username and password dialog. Now it results in "Not Found" html page without the username and password dialog. Also in another post I saw that someone indicated the CPE is encrypted using SSL however that doesn't appear to be true as the browser reports the connection is not encrypted. So is Verizon really accessing 4567 in plain text and what has changed with the Quantum routers that they don't seem to need the same authentication method.

It's possible that the port requires a special user agent or client to access, but will respond with a standard "Not found" page if the right client isn't used.

Without a secure connection, wouldn't using a User Agent or just a URL be a massive security issue (not that a username and password is any better)? Anyone in the middle in theory could intercept that plain text. Their new My Fios app can setup guest wifi access and change other settings remotely, not to mention Verizon can push firmware updates so I'm assuming anyone with that magic URL could gain at least partial control of the router. I also wonder if you could flood that port with enough requests such that you degrade the performance of the users trying go outbound?