Looks like the drivers side corner and the rear full trim panel don't line up along the full seam but what I was referring to was at times you need to adjust those panels to the trap door when you can't adjust the trap door to them.
But lets focus on the trap door since its the simplest of the two options.
I would try and manipulate the two upper brackets that attach the trap door to the top of the frame where each side is held with two small screws
This is a 68 version but it was handy - already in the system and I think they are the same as 67
If it will not move rearward check for obstructions especially if the car had a fold down installed at some point