That is true for the FM2, FM2n, FE2, FA, and FM3a. Not true for the FM and the FE.
A link showing a pic of an FM body with the button plainly in sight is here: http://www.flickr.com/photos/marcus20/3618725672/
APUG: F2AS x2, F, Nikomat FTn
Nikkors: 18-70/3.5-4.5G AF-S DX (f/D200), 20/3.5 UD, 50/1.4 AI, 80-200/4.5 AI, 85/1.8 K, 300/4.5 ED AI
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