I have a set on my Interstate that are 15+ years old. Fit is good except that the front of the muffler tapers all the way to the opening rather than having a 2-3 inch straight section at the clamp. This causes the muffler to be closer to the kickstart than mufflers with the straight transition. A Mk3 kicker gives enough clearance, but with the early style kicker it would foul against the muffler when kicking. The sound is a little deeper than most but not objectionable.
Rocky Point Cycle was a re-seller for EPCO when Stan owned it. New owner (RoadScholar) is a forum contributor, so you might want to check with him also.