Never heard of a spring rack on the front, though I suppose it isn't impossible. Aerodynamically I'd think it'd be more bad than good.

I have had spring racks that clamped to the seat post before, but it seems to me that those had leg stays that went to the rear hub.

Either way, it looks like the only attachment is the clamp to either head or seat tube. Without some sort of additional support, it would seem to me like it wouldn't be very stable with any sort of cargo on it.