Any Ofieri items you may have picked up as random loot previous to completing the quest From Ofier's Distant Shores will count towards the items needed.

Do not sell the saddle if you plan to try for this achievement, as it's the only time you can obtain it as he won't race again and it's not sold anywhere else in the base game.

Simply having it in your inventory will suffice.

You do not actually need to wear any of the items to get the achievement.

Instead, go get the diagram from Zuetzer Castle and then follow the quest to completion. A possible workaround is to start the expansion as a standalone and not talk to the Ofieri merchant. The related quest is known to be bugged.The Witcher 3: Wild Hunt - Blood and Wine Review You must then go to a master armorer ( Yoana in Crow's Perch or one of the armorers in Beauclair) to craft these for you and, once you acquire the last piece, the achievement will pop. Now, complete the quest From Ofier's Distant Shores to get 4 diagrams to craft the 4 pieces of armor for this achievement. You must race and win against him to get the Ofieri stock saddle. Then, mention his horse and he'll offer to race you.

To start, talk to Dulla kh'Amanni, the merchant at Upper Mill, and buy the Ofieri blinders, Ofieri saddlebags and either the Ofieri decorated saber or the Diagram: Ofieri saber (the latter will require you to have it crafted if you go that route).

Ofieri decorated saber (or Ofieri saber).

Hearts of Stone expansion I Wore Ofieri Before It Was Cool is an achievement in Hearts of Stone expansion and is achieved by collecting all the Ofieri armor and horse equipment along with one Ofieri sword as follows:

Overkill witcher 3 achievement