I wouldn't consider 1970's Silverado (or Sierra Classic) comparable to Denali market positioning. Besides, at that time, Ford matched them with XLT Lariat-and Dodge with Adventurer SE. Luxurious, sure, but none of those sufficiently distinctive to merit called Upscale.
Prospector was a package that was available in addition to trim levels, as Explorer was to Ford pickup trims of the time. I personally don't consider either of them upscale enough to compare to EB package. Stuff like that Rumble Bee Dodge example is like their 1970's "Macho", "Warlock" or "Lil' Red Pickup"-perhaps luxurious, but again not upscale.
Eddie Bauer, Denali and maybe Jeep's Sahara trim had cachet. "Gentleman Jim" and "Beau James" (lol) might've fit the bill, but were just special editions.