There are 2- 5/16-24 x 1-1/4" flat head bolts that secure the box the the c-channel of the MFT. The 5/16 nuts fit the channel well, as do the bolts. I believe the closest metric would be an 8 mm.
You can see the heads of the bolts in the picture.
I cut them with the TS-55 on my MFT-3. I cut the "v" then size it to the groove. It needs to be wide enough to make up for the lip on the groove. I think it ends up being 7/8"?? I glue this to a piece that gets trimmed to match the table top height, no reason you couldn't be slightly below. This made up piece then gets Domino'd to the panel of the box.
I've started saving the "v" drop offs from other jobs. Should save me a step.