Is there historic graffiti on Alcatraz? Given the above question, please answer with reasoning first!

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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Native Americans occupied the island of Alcatraz in 1969. Wall writings from the Native American occupation has been preserved and in some cases, restored completely.
Therefore, the answer is yes.