I never ordered anything from Lake Geneva's Dungeon Hobby Shop, although I did have several of its catalogs at various points (all long lost, alas). Reader Todd A. Gibson has managed to hold on to a manila envelope in which a 1981 catalog was sent to him. He scanned its front and back, because they're covered with some artwork I've never seen before by an unknown artist whose initials seem to have been "L.R." (or perhaps "L.K."). Todd graciously allowed me to post the images here for everyone to enjoy.
This is the front of the envelope. You can see a D&D-style troll menacing a party of adventurers, consisting of a magic-user and elf (notice the latter's Keebler-esque rather than Tolkien-esque appearance), an armored fighter, a monk-like cleric, and a Viking (or a very tall dwarf). Notice that the MU is employing a torch to hold the troll at bay, while his companions prepare to use a hose connected to a canister of sulfuric acid to deal with the foul beast.
Here's the back, with the victorious adventurers celebrating by using the troll's burning corpse to roast sausages.