Venom Spurs / Graft Weapons and Weapon Fusions

As Venom Spurs and weapons gained from necrografts are given an item level, can they be given Weapon Fusions?

I don't see why they couldn't. I don't remember seeing any rules stating elsewise.

Venom Spurs aren't weapons, they're cybernetic systems. That's why, right now, it's impossible to be proficient with Venom Spurs, let alone focused or specialized. You can only apply a weapon fusion to them if your GM rules that you can weapon fusion anything, owing to the rules on improvised weapons, allowing you to apply fusions to e.g. chairs.

By contrast, Bone Blades are weapons, so you should be able to apply weapon fusions to them just fine, using the standard rules.

Venom Spurs aren't weapons, they're cybernetic systems.

That sounds like a FAQ candidate.

Would venom spurs be treated as a 'natural weapon'? just added cybernetic/biotech way?

Might be good somewhere to list that cybernetics come with proficiency.

Though then you do run the risk of "well. I cybernetically implanted this heavy weapon into my arm.. So i'm proficient now!"
although, I honestly don't think that would be a problem but i don't know all the cases

My main question on the venom spur is do you have to use the venom the first time you attack with it, or can you choose to attack without injecting and save it?

Venom Spurs aren't weapons, they're cybernetic systems.

Technically they are biotech, not cybernetic

Would venom spurs be treated as a 'natural weapon'? just added cybernetic/biotech way?

That's pretty much how I see it.