Lenses and secondary skill kit bonuses

Secondary skill kit bonuses are gained from having items with them that apply to the current skill, in the inventory. However, the only case of bonuses come with lenses.

The question is, is it consistent to expect that lenses only provide bonuses if worn? If so, should general rules be applied that items that give skill kit bonuses only do so, if placed in the effective slots?

I suspect it is the case, but this needs to be checked.