Bioprof, the inlay is silver with a brass center.
The way it's done is to cut out the silver in the pattern you want. Then cut out the center that you want to highlight.
Next super glue it to a piece of brass the same thinkness as the silver. When the glue is dry, take a needle sharp scribe and scratch the outline of the cut-out into the brass.
Wave a torch at the 2 pieces of metal and they fall apart.
Now, carefully cut the brass inlay out, coming
right up to the line you scribed, until you touch it with your jewlers saw or your files.
When it's done it will fit into the cut-out as if it grew there.
Solder them into each other, but also put a few pieces of scrap brass arount the edges of the solder joint, on the back side to act as "splints" to hold the pieces togather, so they stay there when you bend the compleated inlay to fit the form of the stock.
Inlet it and pin, and sand smooth.
Easy!