I don't have the part number, but I went into the dealer parts section to ask about a replacement Passenger Side hinge cover/cargo deck panel...
I was told it wasn't available separately ,from the entire rear storage floor/deck assembly... Somewhere at $3000+...
So I said thanks I'll use some Christmas Tree push in fasteners...
I used 5 "trees" total. Got the Skirt Tree Set on Amazon...
I used a small 3/16" drill bit to drill a pilot hole from the underside of each broken attachment point.
Then I used an 11/32" drill bit to drill through the panel from the "Top side"... This also cleaned out the remaining broken plastic stuck in the attachment rail...
If you are careful, it will all line up and is a relatively clean look when complete.

The 20mm/10mm Skirt Tree with 16mm head

11/32" drill bit

Flat cargo deck

Part way up power unfolding for passenger seating

Fully upright, ready for a passenger.
I nearly did the driver side too, but that side has not yet failed...
YMMV, but this was my $12 fix for a really poor cargo floor design...