Two recent sales on the duped one. The other hasn't moved and has a one person history.

Sale 1:

https://backpack.tf/item/564487862

https://i.imgur.com/2TIDvTI.png

https://backpack.tf/profiles/76561198826314938#!/compare/1606780800/1607817600

https://backpack.tf/profiles/76561198230732648#!/compare/1606867200/1608076800

28 keys + Breadcrab + Non-Craftable Prinny Machete

Breadcrab: https://backpack.tf/item/9229727814 - valuing at 2.65–3.45 keys (3.05 keys): https://backpack.tf/suggestion/5fd9aaa3755567178913d281

Prinny: https://backpack.tf/item/5008258259 - valuing at 14.33-17.66 ref (16 ref/0.26 keys): https://gyazo.com/b3bbb61c47c92c5fe010df63d2265486

Total: 28+3.05+0.26=31.31 keys, rounded to 31 keys.

Sale 2:

https://backpack.tf/item/564487862

https://i.imgur.com/9Jk454A.jpeg - discussion to show that it's 40 keys.

https://i.imgur.com/hdESLjD.jpg https://i.imgur.com/j3z40ZS.jpg - discussions to show that the other 35 keys went to a different hat

https://backpack.tf/profiles/76561198826314938#!/compare/1607990400/1608076800

https://backpack.tf/profiles/76561199071478193#!/compare/1607558400/1608076800 (untraceable keys)

Conclusion:

Using both sales gives us a range of 31-40 keys.