Are you talking about the Volcano View? ("You are on the edge of a breath-taking view. Far below you is an active volcano, from which great gouts of molten lava come surging out, cascading back down into the depths. The glowing rock fills the farthest reaches of the cavern with a blood-red glare...")Or did you and your friend also add the lava room? Or (this would be the really interesting case, family-tree-wise) was there already a lava room present in your version?
I can't immediately think of a lava obstacle in any version. (Well, the volcanic rift in GOET0580 and IIRC the very endgame of ROBE0665, in a sense. And the Volcano View is crossable in PLAT0550 and its descendants.)
Infocom's "Hitchhiker's Guide to the Galaxy" (1984) includes an object named "no tea", which is in your inventory for much of the game.