But if you are using an upscale player, and at that one that is not super cheap (Bluray or quality DVD player), then you set the mode to regular or full or whatever it is and set it to 1:1 pixel map (on the TV), and the player itself determines the signal to send via the control menu of the player.
And the upscaling player, if it is correctly following the rules here, will upscale the central 704x480(/576) window to 1920x1080, and send that to the TV.
As to your "edited" point, that "junk" on some DVDs is actual picture information on some DVDs, and it is not overscanned if your setup is configured properly.
Overscan is not the same as nominal analogue blanking. NAB should always always be ignored (i.e. treated as junk), and not factored in when calculating ARs.
DE