If it is one of the older emag valves with the recess at the bottom of the on-off hole and uses the urethane oring for the on-off top, then the pin length is 0.725". Install a black emag quad oring in place of the urethane one and it will work fine in your valve as is. The best thing to do is check the length of the pin. A newer emag pin length is 0.712" and should use the black quad oring. It might work as is in your gun setup, but it would probably be quite reactive. The standard pin length is 0.750" for a retro valve or classic valve..
Except for the Automag in front, its usually the man behind the equipment that counts.