Who would you use to do silver wire inlay on a rifle you provide?
Hi Fleener,
First off, welcome to ALR. Make yourself at home, we're glad to have you.
Now to your question. There may be capable builders who might take on the work, but if the gun is already finished, that could be a problem, as the "wire" (actually flat ribbon) has to be filed flush with the wood and this is likely to remove the adjacent finish and stain. It would be best if the gun is in the white, ready for stain and finish.
Wire inlay isn't as hard as it looks and you can make the necessary tools yourself. Practice on some scrap similar to your stock. Who knows?
-Ron