Possible Clues:

• Booker T.'s guys
• Booker T.'s bandmates in '60s R&B
• Sporty British autos
• Booker T. & the -- (1960s band)
• Eng. sports cars
• Booker T. & the ---
• Booker T.'s band, with 'The'
• Booker T and the ___
• British sports cars (Hint to the buried treasure: The G in this answer is also the first letter of the word GOLD, which can be seen running diagonally down to the left. Can you find the other five diagonally hidden pirate treasures?)
• Booker T's backup