What type tube steel does it have? Horn blanks are available and you can shape them or have someone shape them. Can you give a run down of the marks on the flats? It should have had a menacing muzzle which will tell if the tubes have been cut. If you don't have a "Crown" over "W" on the flats the constrction was less than 0.2mm.

Kind Regards,

Raimey
rse