on my 87 300e, the round red plastic insert in the top, which contains the two nipples for the rubber bits, is loose. Is it supposed to be tight and stationary? Should it now be replaced because its loose? Thanks.

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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)