I know it’s still early in the morning, but as of curiousity I checked if vanilla quest rewards are present in the collection, but they aren’t. I randomly checked a with a BC quest, and that reward is in the collection.
I don’t have any transmog unlocks from quests I’ve completed, even quests that are still in the game in Outland and Northrend. The game just doesn’t seem to be using quest completion data at all, just what items you physically still have, unlike when Legion introduced the wardrobe system and retroactively unlocked appearances from every quest that had been completed.
There seems to be one exception: if I still have one of the rewards for a quest in my bag, then I also have the other rewards from that quest unlocked… well, sometimes. For example have Soul Harvester, the scythe-like staff from the Warlock ST quest unlocked, even though I have the mutually-exclusive trinket reward instead sitting in my Warlock’s bags… but for some reason Robes of Servitude, awarded from literally the same quest are not unlocked. I think maybe it only worked for weapons? I have a few weapons from random WotLK quests unlocked that seem to trace back to other weapon rewards for the same quests that happened to be thrown in an alt’s bank and never cleared out, but no armor of any kind.
There’s clearly some intention to retroactively award appearances, or whatever functionality turned my Abyss Shard into an unlocked Soul Harvester appearance wouldn’t have been implemented, but evidently something isn’t firing correctly, and the fact it only seems to affect weapons and not armor is especially strange. Does some of the functionality rely on the changes Legion made to armor types, and needs reimplemented to work prior to that? There’s even an appearance in the appearances tab that cannot possibly ever be obtained by a single Classic character without retroactive unlocks, because it was taken out as a quest reward in a patch prior to Classic’s starting version - the Speedy Racer Goggles.
I really hope this gets fixed, as my main focus for the last several months of gameplay was grinding out Loremaster and completing as many appearance-awarding quests across multiple armor types and both factions as possible. If all of that work was for nothing except the handful of rewards I didn’t get around to vendoring, or if we have to wait for Legion Classic for the unlocks to work properly, then I really can’t see myself bothering with the rest of Cataclysm.
EDIT: If by “present in the collection”, you’re asking if you should be able to see them, not whether they should be unlocked, that’s normal. Appearances without any source are hidden by default, and can only be seen if you’ve unlocked them. My Retail character has pages of Vanilla weapon appearances, along with other things like removed Legion Artifact appearances, but anyone without those available wouldn’t see them at all.
I meant the already collected filter, as paladin there are not too much plate rewards from quests in vanilla. I checked the shoulders, and even the quest check script said I did the quest, it doesn’t appear in the collected part. But for existing quests you can even see those outlooks you don’t learned yet.
With how many bugs are present in the current version of Cataclysm Classic, it’s very likely it’s a bug. I was also surprised by the lack of appearance options.