If you mark a message unread, does it still say you read it?

[Ice Cream Sand Witch 1650]

Sometimes when I get a PM, I read it and then go back to my messenger to mark it unread because I need time to formulate a response. I know some people check to see if a message they sent was read (I do it myself), and I mark it unread because I don't want them to think I'm ignoring them.

Does doing this actually change the "Read" part in messages back to "Not read yet", or is marking unread just supposed to be a reminder and doesn't actually make it go back? Apparently with Facebook, if you mark a message unread the "Seen @ time" check mark still shows, so I'm wondering if it's the same here.

[Ikaru 107]

Yes, the read status on the other end doesn't change:

(from the test account's perspective)

(on "my" end, marked unread)