The one iused many moons ago was a cooke one. It didn't have anthing - spike etc - on the bottom or underneath the stack . What it did have is extra bars on the bottom/back of the sides the pinch the bales in more than the rest of the sides, so (if have totally confused you) the bottom layer of the stack was held tighter than the rest.
I remember them riding well when loaded but like a bone shaker when empty. These were a real boon when they came out because prior to that we had to hand ball the bales onto an artic then hand ball them into the shed. Once these came out they came from the field in 56's or 48's for hay, then were lifted into the shed by a duplicate attatchment for the fork-lift - a lot easier. However we were expected to do more!!!!!