Near sunset, golden rays striking a clear surface or water can produce a scene expressed through the imagery of gold and silver. The poet is not primarily discussing two metals; the image depends on colour, radiance, and reflection.
Water that appears silver-bright and rays that appear golden make a composed visual analogy. The effect lies in the arrangement of colours, not in a bare assertion that “water is silver” or “sunlight is gold.”
The presence or absence of a particle is a separate stylistic question. First establish the underlying composition of the image, then classify its verbal form.