Having been on both sides, working as one of those Sheet Metal guys and for a different company that needs to send stuff to Sheet Metal guys I’d suggest your best option is to model in Sketchup and create a dimensioned drawing in layout for them to redraw from scratch.
As a former Sheet Metal guy I’d much rather redraw something than rely on someone else’s work.
SketchUp is a face modeller. A 3D export from SketchUp to any format will represent flat faces as flat faces. “Round” surfaces, holes etc. are represented with these facets. When edges are exported to DWG SketchUp circles and arcs are transformed into AutoCad circles and arcs but faces do not follow these.