Upload & Sell: On
Probably not. The NeoTec has an unusual foot, with the fold-down foot bracket (which I removed from mine), and the screw ball foot holder/spike.
The base of the 681 monopod is much more simple, and is obviously matched to the 678 base. It looks like the diameter of the 678 base will fit that of the 681 monopod (and others, no doubt), while the NeoTec has its base adapter on a sort of screw-clamp system. I figure the diameter of bottom of the NeoTec tube is larger than the others. OTOH, if the NeoTec diameter is compatible, then you could probably remove the foot assembly and attach the 678 base. OTOOH, I wouldn't bother, myself. I use monopods and I use tripods. I have no desire to create a wobbly 'monotripod', when a real tripod would work so much better. YMMV.
The B&H site offers circumstantial evidence, as the 681 list of accessories inbcludes the 678 base, while the NeoTec does not - it only has a "foot shield".