A rail assembly (530) includes a rail (540) and an adapter (640). The adapter (640) may be slidably interconnected with the rail (540) via a first rail channel (604a) on a first rail side (600a) of the rail (540), and may also be slidably interconnected with the rail (540) via a second rail channel (604b) on a second rail side (600b) of the rail (540). The adapter (640) may be inverted (whether installed via the first rail channel (604a) or the second rail channel (604b)) between two different orientations that dispose a mounting flange (670) at different elevations to accommodate two different mounting configurations.