All of this really started with the modification of the original Clouser coupler. How do I know this? Because I'm the one that made the original modifications. The shelf couplers came into being because Jimmy was helped Norm with the final product (for now) and these are an offshoot from all of that.
One of the interim coupler boxes was far different from the current production. They look more like a Kadee box. Why do I mention this? Because the shelf couplers should fit in the older box and they allow for more swing of the couplers. I know Protocraft has a decent supply of the older boxes. Norm is away for the Thanksgiving Holiday but he should be back is a week, or so. Give give him a call and get some of the boxes if you operate with tighter radius curves.
I do remember making the modification that allows for the short steel rod installed in the lift pin. We drilled out a Clouser, created a slot, and glued a short piece of steel rod in the opening. I found cutting up a paper clip to be the easiest. Soft steel, easy to cut, readily available, cheap, and one clip will make a lot of pieces.
If needed, I suppose I could create a few photos.