Good Day. A warm welcome to the HP community. I reviewed the case regarding screw kits required for the computer. Superb description, and terrific observations made before posting. Kudos to you for that. 🙂
To assist you with accurate information I would require more information regarding this.
Did you check HP part store for the different part numbers?
Did you try to contact HP phone support in this regard?
For now please visit HP part store via this link: http://partsurfer.hp.comand select the country. You might find a phone number to call. Then follow the on-screen instructions.
Also, you could contact HP phone support directly to order the screw kit if available.