Yeah, the black accent has faded off your grille. The difference in 71/72 grilles is that accent paint, but there's more. That center vertical is also wider. Around the openings is a raised edge the black accent goes into but chrome remains on that edge. Much like the look of 67/68 Chevy grille trim. The 71/72, if you look at it long and hard, can appear to be separated like a Pontiac. If that black was body color it would be more obvious.
I go with as built as well, but for whatever reason, ever since I've had my '72 K2500 I've had another color envisioned. At that time I had two hi option '72 K/20s I never planned to deviate from the SPID on. Now that it's my only 3/4t 4wd it has gone back to keep original and now to build it as the ultimate truck I always wanted from factory because it's my keeper and a tribute to my longtime devotion to these 3/4t 4wd GMs, over 40 years now.
Here's a real life sample of what you are considering for your GMC. I have the Saddle dash pieces but haven't installed yet. And the tilt is a rebuild I bought from Cheyenne Superman in '91 for another truck I had, as well as the seat and dash pieces: