My indie heard the noise last weekend and said I need the emergency brake repair kit (12442008720). Shouldn't this be checked when rear rotors are replaced, or could something have gotten loose when he replaced those rear rotors?

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87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)