I was poking around in the 1e DMG's section on experience points due to a discussion on /r/osr and stumbled across this on page 85:
Division of Experience Points:
How treasure is divided is actually in the realm of player decision. Experience points (x.p.) for slain monsters, however, is strictly your prerogative. It is suggested that you decide division of x.p. as follows:...
Italics mine. And then the procedure for dividing XP only discusses XP from monsters. Further down on that page there's a discussion of XP from treasure but it discusses only things like lowering the ratio for XP from GP if the party was stronger than the monsters it took the treasure from, the value of magic items, and when XP for treasure is awarded - nothing about how XP from treasure is divided.
I think this could be interpreted in support of my old speculative post about players controlling how XP from treasure is divided through their choice of who to allocate treasure to. The heading where this note about treasure being divided by players is explicitly about XP allocation. The existing division procedure only covers XP from monsters, and no procedure for dividing XP from treasure is provided. I wouldn't say it's clearly Gygax's intent that XP from treasure should be divided as the players choose, but I think it's the most reasonable interpretation of the gaps here.
Tangentially, the other thing that surprised me in the 1e DMG's section on awarding XP was:
SPECIAL BONUS AWARD TO EXPERIENCE POINTS
If your campaign is particularly dangerous, with a low life expectancy for
starting player characters, or if it is a well-established one where most players are of medium or above level, and new participants have difficulty surviving because of this, the following Special Bonus Award is suggested:
Any character killed and subsequently restored to life by means of a spell or device, other than a ring of regeneration, will earn an experience point bonus award of 1,000 points. This will materially aid characters of lower levels of experience, while it will not unduly affect earned experience for those of higher level. As only you can bestow this award, you may also feel free to decline to give it to player characters who were particularly foolish or stupid in their actions which immediately preceded death, particularly if such characters are not “sadder but wiser” for the happening.
Gaining XP for dying, rather than losing it! Wild!