Normal ones have three point of contact, the one in your pic only has two, door one does not so much take any load but stops it shaking about to much, bit like your feet carry you up the stairs but every now and then being able to hold onto the...
A thin smear of grewase on the pins to stop things sticking, then injecta. littel silicone selamt into the femal
Bet it will catch as you refit the flaps, maybe try a thin smear of grease on the pins, then some silicone sealant in the female...
Iirc the series x member has some holes in the bottom face, this is for a piece of angle iron to attach to to allow the drop plate to fix to the angle iron to save twisting the rear x member.
Think only the other week someone on here was selling a freshly skimmed 200 flywheel.
As it is an arse job to get box out once the car is together I would be inclined to sort it out while it is easy to get at.