It appears there are two rectangular spots on the bed top edge on each side that "should" be for mounting things (most truck beds have these attachment points). Should be able to use those as tie down points for soft goods on the tonneau cover.
Sure glad to confirm the HSC tailgate can handle 500lbs. IIRC the Maverick tailgate can't handle that much and couldn't even handle two of me. I noticed on one of the Maverick videos that when the Maverick tailgate was down, only the passenger side cable stop was tight. The drivers side cable still had slack in it. What's that say about Ford quality? Was the tailgate bent? If not, it will be getting tweaked every time someone sits on that side. That's just a BIG no-no on tailgate part/assembly(?) quality.