[SS Tim]

Interesting truck. Definitively a Chevrolet and not a GMC as purported initially. That alone made me suspect the truck in light of the Chevrolet emblem on the sticker. The fact that it does not have a "Deluxe" badge below the "Custom/20" is also a point. The lack of the "Deluxe" badge made the bright vent and windshield trim suspect as they were not available on a "Custom" trim level.
As it sits, per the SPID it is a pretty run of the mill, abet nicely equipped, Custom/20 Custom Camper save for the "special paint". Looking at the pictures shows the interior metal to be black vs the ochre color it would normally be. If the truck is/as original the black would qualify as "special paint"
The stickers are no doubt a local dealer added items. The artwork just does not seem polished enough. If they were factory we would likely see a 9000 series decal call-out on the SPID as well.
It was very likely a dealer/regional special run, 2800 seems like a large number. There may have been different stickers for other series trucks or engines with this specific paint scheme. As a "special truck" it really is not of greater than normal value except possibly to a very select market like the selling dealer's family.