Basically they are the same, except one is gold and the other silver. Silver is a gene that removes gold pigments from a bird, leaving only black and white coloring.
Silver is also sex linked. GLW rooster over SLW will give you SLW cockerels and GLW hens. SLW rooster over GLW hens give all silver offspring.
However there's a "but".. while silver removes gold, it often does not work well on the gold in the hackles and saddles.. extra genes to remove the gold in those areas is required for a "clean silver" bird. So the result of crossing the two often gives a SLW rooster with off color areas.
So they'll be laced, and come in SLW or GLW versions but how "clean" the white or gold centers will turn out is entirely another matter. It can be a challenge to get the color clean again- possible but will require raising and culling birds.