It's my understanding the Italian company was Verlicchi who is still making motorcycle frames. See their web site:
http://www.verlicchi.it/eng/
A few years ago I emailed the company asking for any info on the frames they made for Norton. I got a reply, but was told the records no longer existed. The following is from the web site--Norton is mentioned under "1964-1971".
Verlicchi History
1934 - 1963
In 1934 Nino Verlicchi (1914 – 1996) and his brother Giuseppe opened a small workshop in via S. Carlo, in the centre of Bologna, for the production of tubular steel structures, in particular handlebars and exhaust pipes. They worked for Bologna’s engineering motorcycle industry, at the time led by companies such as CM, GD and MM.
In 1946, after the 2nd world war, Nino Verlicchi reopened the shop in via S. Carlo. Thanks to the know-how gained during the war (working in military workshops), he began to design and produce his first complete motorcycle and bicycle frames. It was during this period that he patented and produced the first innovative integral use of frame-supported suspension frame for the Ducati “Cucciolo” engine.
Increased use of frame supported small engines led to significant growth, and in 1950 the Company moved to a 300 sq. m. industrial shed in via Andrea Costa (Bologna), expanding to 20 employees.
During these years, the Company started a close relationship with the Italian motorcycle industry, and Verlicchi soon became the main supplier to Ducati, Morini, Mondial, Cimati, Malanca and BM-Bonvicini.
1964 - 1971
In 1964 the Company acquired a new 3000 sq. M. factory in Croce di Casalecchio (BO) and expanded its staff to 100.
These new premises were immediately organised for maximum efficiency, with specialised departments for each step of the frame production process.
This allowed Verlicchi to expand its business horizons, and to deliver the first supplies to important new European manufacturers such as Norton, Zündapp, Triumph, Laverda, Guzzi, Fantic and Minarelli.
Those were the years of the greatest popularity of a new frame designed by Nino Verlicchi. This frame, known for adaptability and reliability, would equip a large number of models, such as Benelli, Fantic, Moto Morini and Villa, for more then a decade.
1972 - 1989
In 1972 the Company inaugurated its 16.000 sq. m. factory in Zola Predosa, close to Bologna. This is still the Company’s operating centre.
In addition to the expanding of various production departments, the Company created an independent Technical Department to co-operate with Customers in product design, development and industrialisation.
Thanks to this strategy, Verlicchi has intensified its collaboration and supply relationship with international partners such as Honda Motor.
In the early 1980s the advent of aluminium machining was a turning point in the Company’s evolution. By applying exclusive research and know-how, the Company offered its customers innovative frame solutions.
In 1984 was introduced a frame for Bimota entirely manufactured in light alloy, the first in Europe for mass-produced motorcycles. Similar products were introduced in the following years for Ducati, Aprilia, Yamaha, Cagiva, Beta and Montesa.
1990 - 2000
In 1990 Verlicchi became a supplier for BMW motorcycles, and in 1993 for BMW cars. Very close technical collaboration with this important group provided greater knowledge in the use of light alloys. The result was a frame obtained by assembling and machining of cast aluminium parts.
At the same time, the first weight-bearing frame structure in light alloy were developed for the car industry. These are now extensively used in mass production.
In the early 1990s the Company entered another sector: the design and production of special light alloy-frames for high-end mountain bikes and road bikes. In 1997 the Verlicchi Team won the downhill world cup.
In 1997 Verlicchi inaugurated Verlicchi Casoli S.r.l. on a 21.000 sq. m. space close to Chieti. This unit mass-produces steel frames and components. At first, the unit aimed at satisfying the growing needs of the nearby Honda Italia plant, but production lines for other customers were soon installed.
In 1998 Verlicchi defined the products that play an essential role in its market. Of special importance are the light-alloy frames for the BMW safety cell vehicle (C1) and similar frame solutions for the city-car.
These new structures are built in a new 6000 sq. m. factory close to Bologna, inaugurated in 1998.