Supernaut wrote in Sealed AD&D early rulebooks:Brian, while I’m not an authority to the formatting, I believe the shrinkwrap multiplier you circle in the header would be more helpful with the suffix “where applicable”, typically being modules, accessories, box sets, etc., where noted. The core AD&D rulebooks you reference from your youth were not shrink wrapped. The Acaeum’s documentation explicitly calls this out at the bottom of the Monster Manual page. A simple eBay search for sold shrink wrapped AD&D modules will validate what you’ve read regarding their valuation.