That is the colour I wish I could have done my coupe in...alas, that dark will show even the tiniest body finish flaw...so while it looks great, as with all dark colours you need to make sure everthing else is up to it.
But...your search for excellence (yes, LOL, blatant bias here on my part) has caused me to deep-dive into my stack of Dealer Brochures...and I knew that there was a 1980 Diplomat booklet which had the coupe in that colour...indeed, I found it!
Take a look at the attached scans. I have the much higher res originals here, email me if you want them. Anyways, I did finish the interior of my coupe if dark blue, the closest match I could find at that time to the factory stuff...let me know if you want to see a few pics.