I should probably do this as well, since I plopped one in there before I realized I needed to do anything else. Funny thing is, when I was looking this up, it seems there isn't even all that much software that uses the FPU for the ST, right? I got a few for cheap (I think I even still have a spare or two) and plopped one in all the systems I have that had sockets for them.
Atari 8Bits: 800xl, 600xl, XEGS, 800, 130xe, 130xe (VBXE, U1MB, Stereo POKEY)
Atari STs: 1040STf (broken shifter), 1040STe, Mega STe, TT030, Falcon (CT60e, SuperVidel)