We broke one on EJ when I landed on it, the repair was significantly easier than making a new one.
We also have a mould you are welcome to use. This one is asymmetric when viewed from the side of the boat and raises the stock further from the water. Similar to Phil's mine flat packs, but unlike Phil's it has a tendency to do this when you handle it (it is only held together with tape). Can happily make a part from the tool here or send the parts (the one for the AS is different again, as the gantry is offset from the center line on plan).
The choice for moulds appears fairly broad, would suggest you base the decision on bits measured from your boat.
These are key as they do vary...
1) distance between gudgeon on stock
2) distance between slits in the hinge supports