If they're like the E39 button covers, once they go, they're gone. Sometimes they'll weakly hold on and be okay if you don't touch them. Fortunately there are sources for the individual button covers or entire units from donor cars in support of the E39. Never seen anything like that for the E70 but never looked either.

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8/2011 X5 xDrive35d Sport, Black Sapphire Metallic, Black Nevada Leather, Fine Burr Walnut Trim
2/2001 M5, Jet Black, Exclusive Complete Black Walk Nappa Point Heritage Leather, Black Cubic Trim