See - that's why I love this forum, not only does it go off on a tangent, its all general idle, nice-to-read banter....
Its a genuine Guzzi, the Ercole made from 1928 to, I think, the early 70's. Engine was a 500cc single. That's quite a production run. It must have worked.
@Gimlet - you appear to have found a thread you like living in for a while, don't stay here too long as others will miss you