Duplicate in geometry, or with prefabs?

I want to model a large hero asset (a space station) and then stick lots of little surface items like handrails onto it. Many of these items are not unique.

I know I can either duplicate this geometry in blender, or I can create individpal prefab assets and duplicate those in Unity. At what point does it become more efficient to use prefabs for these details? They are only a few polygons and have no scripts whatsoever. Is the overhead of individual objects and mesh renderers higher than duplicating polygons in the same mesh?

Multi objects may allow for better culling, and maybe with a hundred objects and a few thousand polys it makes no difference overall... your thoughts would be a great help, thanks!