Do sidebearings matter when creating components?

I’m working on the assumption that only the side-bearings of the glyph itself are used. I’m setting the side-bearings of the components to zero, but if I happened to miss one, would it cause any problems?

Thanks in advance.

What kind of components do you mean?

I’m using combining marks, but I’m more concerned in this instance with serif components.

For combining marks and corner/caps, the spacing doesn’t matter.

anywhere the components hook on via attachment marks the side bearings are irrelevant other than cursive attachment