They are definitely not Campy pads, as none were ever that long, or had a notch for a retaining pin.
Given the length, I suspect they're more likely
Shimano V-brake style pads, which used a cotter pin retainer. scroll down to the
V-type inserts at the
KoolStop site, and see if these look right.
Of course the devil is in the details, and others made similar shoes, though many other brand shoes use the same insert. To be sure you'd need to measure hem at the widest part of the back dovetail, and measure the distance from the back to the cotter pin cutout.