http://www.corsair.com/en-us/750d-front-and-bottom-replacement-dust-filter this one is for sure.
And the answer is, no it isn't. Bottom filter on Corsair is 127,00 mm x 254 mm, and FF142 is 320 mm x 155 mm. Quite a difference.
Just FYi, front is 194.98 x 324,00 mm, rear is 165,00 x 140mm, rear small is 48mm x 182mm, and top is 475,00 x 195 mm.