Possible Clues:

• Kemo Sabe
• Silver's rider, with "the" (In this answer, note letters 4-9)
• Fictional western character associated with Tonto
• Green Hornet's great-uncle
• Masked man of westerns
• Western hero making advance, reportedly, accompanied by guide
• User of silver bullets
• Silver topper?
• Silver rider, with "the"
• Cowboy who rode the end of 41-Across