The flat spring is held to the front panel with two screws on the left above and presses down on a bent tab at the bottom of the arm on the right to hold the glove box closed.   When the glove box is open the same spring and tab holds the door fully open.   The cardboard glove box fastens to the holes in the portion of the instrument panel that is bent upward in the picture.

These are my notes on the glove box mounting.  The brackets and springs on the right and left are identical but the cardboard glove boxes themselves are not (both "L" and "R" versions are used).  Part numbers from Univair are:

Glove Box Door 415-51096
Glove Box Spring 415-51020
Glove Box 415-51028-R/L

Since I had an original panel I tried to match up the colors to the PANTONE Color Selector 1000/Coated standards.  Here is what I came up with:

GRAY = Pantone 417C
RED = Pantone 498C