This 1st print of Ghost Tower of Inverness by Allen Hammack only saw 300 numbered copies for sale at Wintercon VIII in 1979 (some unnumbered copies exist – see The Acaeum for more details). Lime green cover, with loose sheets inside.
The usual Inverness module is red, and coded C2. More about the Competition series of Advanced Dungeons and Dragons modules at my RPG Reference site.
These photos were from a 2018 eBay auction. I’ve got them archived here for posterity.