It is extremely important NOT to TRUST or ACCEPT information regarding recall work performed on bikes of this era that comes from MOTO GUZZI. Guzzi was terrible at collecting and collating information during this era. Some dealers reported doing recall work that was never done. There were many things that caused this problem, regardless trust your own eyes only when it comes to whether or not any recall work was done. If you pull the rocker cover off and the valve retainers are aluminum the recall for valve train was probably done. Most of the hydraulic lifter bikes had a sticker proclaiming this on the tank. There were other recall campaigns on these bikes including lower triple trees and throttle closing cables added to the twist throttle. I mention not trusting anything but your own eyes because these defects or issues could be life threatening. A stalled bike at the wrong time, broken triple tree, or stuck throttle could be the cause of an accident.
Brian