The CAD geometry in .step format is available here. The parts in this file were exported from the LinearSpring.FCStd file after assembly solving, so their initial positions are preserved. The FreeCAD file is available here. It includes the parametric parts before assembly solving.
For this simulation both parts were assigned the average properties of steel. The spring was assigned a spring constant of 90.0 N/m and a damping constant of 0.0 N*s/m.