I read that some prints were stolen and the filmmakers were forced to edit it with alternate takes.
Yes, some sources say the whole film was made of alternative takes, some say only parts of it.
The last reel of the film was stolen and the crew had to finish it with additional footage shot in a hurry so the ending is a terrible. Terence Hill tells of this in an interview I’ve seen on the Internet so search around and you’ll find it.
btw, here’s the “real” topic for Genius:
http://www.spaghetti-western.net/forum/index.php/topic,1179.20.html
I think this topic should be moved to Lost & Found section.