[55-72 GM trucks]

7 months in, might be time to look at adjusting the price closer to what the other NOS ones sold for during the past 24 months. These don't bring as much as people think unless they are early stampings when the anodizing is shinier and more chrome-like, and when the headlight bezels are the early type with no screwdriver slots.
Some grilles come out of the box looking like the shiny side of Aluminum foil, but many of the late 70's and early 80's produced ones came out looking more like the dull side of Aluminum foil - that is the type you have here. Check comps and you will see what these normally bring and maybe that will help you sell it