Sale #1:

https://backpack.tf/item/16506004884

https://backpack.tf/profiles/76561199233427646#!/compare/1770336000/1770940800 ~ no matches

https://backpack.tf/profiles/76561199026390261#!/compare/1770249600/1770336000

Sale #2:

https://backpack.tf/profiles/76561199026390261#!/compare/1774483200/1774569600 ~ no matches

https://backpack.tf/profiles/76561199244343602#!/compare/1774483200/1774569600

https://next.backpack.tf/profiles/76561199244343602/compare?from=1774483200&to=1774569600 ~ 4 keys match here to Unusual #2 (the bot who owned it), the other keys match Unusual 4.0

It seems some of the ref also matches, the stn website appears to list it at Buy it for: 3 keys, 33.22 ref, so it was most likely around this range although I will try to get confirmation on this.

Sale #3:

https://backpack.tf/profiles/76561199244343602#!/compare/1774656000/1774742400 ~ added 20 ref ontop for 4 keys

https://backpack.tf/profiles/76561197999173629#!/compare/1774483200/1774742400

Keys priced at 54.33 - 20 = 34.33 ref = 0.64 keys

Taking 3.65 keys.