The older studs have a screw inside that you can lock down against the body for more stability whereas the modern ones don't so they can wobble a bit, but you should be able to get these replacement studs from an Ibanez dealer. I prefer the original edge as I find the balance more comfortable and there's something about the visual design that I think they really got right.
Oh yes, as above the edge pro rout is too small for an original edge. Original edge and lo-pro edge are interchangeable though.
