Thanks for the info; much appreciated. Staintune is made of stainless too, IIRC.
The 'baloney' exhaust was a Guzzi factory race item, almost certainly crafted by Lanfronc. I have images (somewhere) but they were most commonly seen on the V7S race bikes developed by Tonti...pre-DeTomaso. I'll dig one up and post.
Here's a neat system that I imagine few people have seen. This is the Crossbow (Fairings) 850 LeMans. The black chrome exhaust was also offered. Black chrome...in 1977! These are rare pics, scanned from 35mm and sent to me by the former owner of Crossbow for an article I wrote. I fell in love with it!