Maybe it’s the lighting that is washing it out, but I can’t discern a seam on the back side, where there would have to be for any hinge, even a disguised one. Unless the lid is made of some sort of rubber or flexible urethane? Or, again, it’s lighting.
For that matter the joining line between the lid and body on the front is a bit warped, rather than the straight line needed for a hidden hinge (unless the silver panel is bowed upwards in the center, over the lid):
In addition, that grey detail panel appears to be raised above the edge of the silver frame, meaning there would not be clearance for the lid to fully close if it were hinged (unless the grey panel collapses?).
Surely they did have one with an opening lid (the one McCoy is holding in the first two screencaps appears distinct from the one on display, with an additional panel line and dark spots that could be access screws and hinges), and though I’m trying to find alternative explanations, my brain is having a hard time processing that particular prop’s lid as anything other than fixed. Help!