I have one of the Philadelphia Arms hinge pin guns (1904), and from across the room, it looks just like a Parker. Story I heard/read was that Parker sued Ansley for using the design, so he changed to the more typical Fox frame profile. I don't think I have ever seen a post-Philadelphia Arms graded Fox with the Parker pin, but have seen several hinge pin Sterlingworths. I, for one, would pay a bit more for a hinge pin Sterly than for a standard Sterly, but not as much as I would pay for a comparable Parker VH. I kinda doubt in today's market that a pin Sterly would bring Trojan prices for a gun in comparable condition. Researcher should be along shortly to enlighten us.