Re suggesting from https://backpack.tf/suggestion/65c2a3a553479e308a0c7a47

Price is 4 years old...

Item 1 History https://backpack.tf/item/1823955152

Sale 1

26 keys - from an auction

https://backpack.tf/profiles/76561198349672838#!/compare/1706918400/1707177600 (seller's keys & unusual)

https://backpack.tf/profiles/76561198046353418#!/compare/1706832000/1707091200 (my side)

Sale 2

27 keys 19 ref

https://backpack.tf/profiles/76561198349672838#!/compare/1706659200/1706918400

https://backpack.tf/profiles/76561198325974441#!/compare/1706572800/1706659200

The keys and refined match histories.

https://steamuserimages-a.akamaihd.net/ugc/2378532574952968632/6DACDF9781B9CB927726B4B5D10CF0A97BA8CA50/

Sale 3

26 keys, 25 ref.

https://backpack.tf/profiles/76561199177136435#!/compare/1706313600/1706400000

Key history shows they were in both backpacks. User https://backpack.tf/profiles/76561199177136435 and user https://backpack.tf/profiles/76561198325974441 traded with each other.

Item 2 History https://backpack.tf/item/2816632461

Sale 1 - trade bot

IDK

https://backpack.tf/profiles/76561199043177646#!/compare/1704758400/1704844800

Sale 2 - bulk

https://backpack.tf/profiles/76561199135952616#!/compare/1703203200/1703376000

https://backpack.tf/profiles/76561198311498888#!/compare/1703289600/1703376000

Looks like it was dumped to a bot after, couldn't find the sale.

Item 3 History https://backpack.tf/item/7956382191

Sale 1 - bulk

https://backpack.tf/profiles/76561198048166329#!/compare/1703548800/1703808000

The rest of the sales appear to be between trade bots and their owners or bulk sales.

Going with 26-27, thanks to Sir Spoon the Second and Skycania TTV for helping me out.