Consider the expression \((3^{1024} + 4^{1024})^2 - (3^{1024} - 4^{1024})^2\). Simplify this expression and express it in the form \(k \cdot 10^{1024}\) for some positive integer \(k\). What is the value of \(k\)? Let's think step by step and output the final answer within \boxed{}.
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