One of the things I've noticed in the Temple of Elemental Evil is that there are rooms that are described as richly furnished, or that are in some other way made obviously full of potentially valuable stuff, that aren't detailed. For example, Lareth's chambers are described thus:
"The Master's chamber is lavishly furnished, with thick rugs, wall hangings, and soft chairs, couch, and cushions. Wines, liquors, and dishes of sweetmeats abound."but none of that is given a value. Contrast in more modern games, at least according to my limited experience, where the assumption is that player characters will strip a place clean, and then go back to strip the clean off. For example, Dungeon Fantasy 2 even has rules for bringing back doors, bars, and other scrap from the dungeon.
This is neither an oversight nor an bias against these types of value on the part of Gygax and Mentzer. Later in the supermodule there's an entire room that's explicitly stocked to the gills with <certain valuable stuff>, and it's assumed that the PCs will take some of it; in fact, there's a set of sort-of-rules for scrounging through all the clutter to find valuable stuff. However, there's no hard description of exactly what is in place and how valuable it is. Instead, it's assumed (and frankly stated) that the PCs won't/can't run off with it all.
When I first saw this it boggled me. Why would you have what's frankly a treasure trove and not have a clear value to it? What's going on here? I'm not certain, but let me advance two possibilities.
Possibly, this stuff wasn't regarded as treasure. The old chant goes, "Gems, Jewels, Magic," not, "Sofas, tapestries, silks." If that's the case, then it's kind of disappointing; interesting treasures, even mundane ones, fire the imagination. A bundle of rare Ismaili redsilks is much better than a bag of 300 gp, especially if that bundle is embroidered with the pattern favored by the late King's Consort because of her heritage in the barbarian north.
A much more compelling possibility rests on the understanding that such details don't matter until they matter. To put it another way, Gygax and Mentzer specifically didn't detail all the objects in the room because that limits a GM's creativity, and they understood that, even though this was based on Gary's game, it wasn't Gary's game. If you bought T1, you didn't buy it for to brush up on your Greyhawk lore so you could sit at the table in Geneva; you bought it so you could run it yourself, in your own version of Greyhawk (or somewhere else). In this hypothesis, the authors expected you to pick up on "lavishly furnished" and provide to your players what that means. Is it stocked with decadent bloodwines from the heathen south? Etruvian brandies? Silks spun from the eggsacs of void-spiders? That's your call, and by leaving such details out you're allowed, even forced, to make it. The simple issue of weight and value is easily solved. ("Oh, and generally it's all worth 40,000 gp, but weighs several thousand pounds. What do you want to take?")
I like that second option more, so I'm going to chalk this up as another case of understanding the game to be permissive rather than restrictive. It's a vehicle for your imagination to fall back on to maintain its own internal plausibility, rather than attempting to be the scope of everything possible.
This is a good way. I can always just come up with specific weights and values when the PCs go back to town.