Well... it depends on the book! If your content remains within the borders, then I would say that yes, you leave the outside borders blank. However, since your comic is full-bleed... I would advise that you extend your page a little bit past the crop mark (like maybe 1/2 an inch?) so that the pages can be cut properly.
It's really difficult to incorporate crop-marks post page creation as you need them as a guide to show how you should draw your pages without jeopardizing any content. (ie. panels/speech bubbles appear cut off, dialogue gets stuck in the book gutter, etc.)
Also, I found this (might be more helpful); it goes through each component of the crop mark and has tips for prepping a comic/manga for print.
edit: you pretty much understand how the crop-marks work (nice diagram btw)... just keep in mind you might have to rework your pages if you want them to be print-ready.