There are a couple of ways that the scales could be darkened, not necessarily with a "solution". The first step would be to sand any clearcoat that is on the scales (never handled a wood-scaled SAK, not sure what they're finished with). After making sure the scales are clean and dust-free, step two would be to apply a light coat of a heavy bodied pigmented stain or gel stain. Zar and Old Masters are the companies that come to mind right away. A heavy bodied glazing stain such as that made by Mohawk would work too. Apply the stain, then wipe it off with a rag. Repeat to taste. Step Three would be to seal the scales using either a polyurethane or a lacquer. You're in Jersey, right? PM me and I'll see what I can do, might be able to get you very small quantities of any of the products I mentioned.