From the Fox site.

Don posts here also so I don't think he'll mind me quoting him.

Originally Posted By: "DGKaas"
The rear portion of the fore end is without question factory Fox, IMHO. The shaping and the grooves in the rib channel are the giveaways.Miller triggers are often serialed to the gun. PA trap and pigeon shooters are often associated with Miller trigger simply because Elmer and his sons, Howard and Delbert frequented shoots major and minor in their home state for 75 years and sold a lot of trigger there.

Mike