Not the spring clamps, this is at the axle. On my FJ-62 these was a u shaped channel that goes around the sides of the spring pack and in between the spring pack and the axle right at the center bolt. It holds the rubber spring pads. Sorry, I can't find a good picture right now and since these are re-used with the Man-a-fre ubolt flip kit mine are packed away.
The cause of the broken leaves is not 100% clear but when I offered this hypothesis to Alcan they said it was possible. I also want to make it clear that I'm not trying to blame or discredit Alcan in any way. I (and the shop that installed the springs for me, this is why I do all my own work now) should have questioned the leaf count mismatch prior to installation.