The plating was nickel - it gets very expensive - the pipes are "or should be" standard black iron that are buffed down and plated. Every major city has a plating company that will do this.
As for the pipes - if you have the sizes and can get them off - take them to home depot and have them cut and threaded for you extra long, then cut down with a cutting wheel or if you have to use a hack saw - then buff them on a wire wheel to a bright shine - and drop off to the plating. IF by chance your threads are NOT standard "some are most are NOT" you will have to take them to a machine shop and have them treaded on their lathes - even more expensive.
I could "maybe" copy these but shipping is a killer - plus it is ~ICE~ cold in my shop right now - so I am only working in the basement on cuckoo clocks "my winter work"!
What I would do - bend the broken one back to shape - V notch the crack, and braze it building it high - then grind the braze to shape - fill with bondo - sand smooth - and use the paint we use on the WW2 Anti-Aircraft searchlight mirrors - they will look better then new and no one will know different!