You might want to try Gary Fellers for the sights - 817-346-9633. He is a little unorthodox in his business methods but probably as likely as anyone in the country to have unusual items. I bought a Lyman 48R from him a few weeks ago, mint and still in the original cloth pouch with cosmoline.

The usual routine is to leave a message on his answering machine and tell him what you’re looking for. He will normally call back.

Other than that, you might have some luck on eBay or by contacting higher end gun dealers.

Also, Recknagel (spelling?) may have something.