Wow Dave,Same priciple. Only you'll secure your lower pipe via the stock mount and the upper pipe is held in place with a mount fabricated and coming off the upper shock mount, which is stationary, unlike the swingarm.
If you use chrome clamps with mounting bolts, there's no need to weld to the pipe, although that's usually a better way to do it..
If you make the pipes custom, you can have them chromed, wrapped or sent to a company like JetHot and coated in a silver ceramic coating.
Paul Yaffe makes a set, but not for Ironheads.
Paughco makes a set of Shotguns for Ironhead rigids, only you'll have to make the mounts yourself.
About 1-1/2" from the bottom (scroll bar) and it reads....
Paughco Shotgun drag pipes for Ironhead Sportster Rigid - These Shotgun Drag Pipe Exhaust sets are 16 gauge triple chrome plated steel tubing and are designed for the best fit and ground clearance possible. The ends are slash cut and any correct size baffle can be used. 1 3/4 inch O.D.-34 inch Long Shotgun Drag Exhaust Set fits Ironhead Sportster 1957/1985 in rigid frame only .Chrome Plated. Made in USA. Part#:MW62-619 - our price $162.42 including shipping*