I have a extra one that is a Allem double release. It has the engraved trigger guard like a MX2000. PM if you are interested. Yes, they are a rare trigger. I shoot one in my SC3 and it is a great trigger.
That is the going rate. I am asking $2000.00 for mine. Allem's charges $700 for the releases alone. They are a $2900 or so up charge on a new gun. My release is a extra I bought because they are rare to find even though I shoot pull trigger Most owners keep the triggers with the gun because of the cost. I am lucky to have 2 of them.