In the original US versions of FOR A FEW DOLLARS MORE there was this scene:
Lee Van Cleef has just collected the bounty for Guy Calloway. He sees a poster for Red Cavanaugh on the wall of the sheriffs office. He asks the sheriff, "What can you tell me about Cavanaugh?".
The sheriff says, "About a week ago, he was seen at White Rocks".
Van Cleef says thanks and turns to leave.
The sheriff then tells Van Cleef that someone else has already asked him about Cavanaugh.
When Van Cleef asks him who it was, the sheriff responds: "I'd never seen him before".
As soon as that line is delivered, the original US versions cut directly to Eastwood's entrance scene..where he is walking along just as it starts to rain.
This was the version that played in the film's original theatrical release and on TV.
In the newer, so-called "uncut" version, which is now available on DVD...the scene is the same expect the sheriff says "I'd never seen him before....his name is Manco".
There is an argument that has been going on for many years as to whether this character is known as Manco or Monco. As it turns out, after much discussion with people directly involved in the making of the film (Aldo Sambrell being one among many)---the names are pretty much identical in meaning.
In Spanish "Manco" means a one-armed man.
In Italian "Monco" means the same.
Basically, they refer to Eastwood seeming to do everything with his left hand so that he has his right hand free to draw his gun in a flash, if needed.
Witness how he does everything with only his left hand in his introduction scene in the movie.
He deals cards with his left, fights Red Cavanaugh with only his left hand....and so on.
When it comes time to draw and shoot the three men that come to Red's rescue...then he uses his right hand.
So, yes...he is Manco (or Monco) in this film. It is not a name so much as a descriptive nick-name (like Blondie in GBU).
Incidentally, the best DVD version available of FOR A FEW DOLLARS MORE is the German Paramount release.
It contains a bit of dialogue at the end of the scene where Indio and his men are beating up Col. Mortimer and Manco, that is inexplicably missing from the so-called uncut, remastered version that MGM released in the USA and the UK.
Unfortunately, all of the available versions (except for the Spanish DVD I picked up in Almeria a few years ago) have an out of sync soundtrack in Eastwood's entrance scene which places a loud clap of thunder several beats before Eastwood looks up and we see his face for the first time.
Leone intended that clap of thunder to occur dramatically as soon as we see Eastwood's face.
A great cinematic moment that is spoiled by the soundtrack glitches.
Again, this error is inexplicable..because the thunder clap occurs at the appropriate time in the Spanish version I have, and it used to happen at the right time in the old MGM/UA fullscreen VHS versions, too.
As if you couldn't tell...FOR A FEW DOLLARS MORE is my all-time favorite Leone film and one I have literally seen over 270 times since the 1970's.
Hope my answer has helped, guys!
PS= Stanton, he is also called Manco (or Monco) by Indio in the scene where he is speaking to Nino after they have let Mortimer and Manco loose.
Indio: "Nino, how long have you known that Manco was a bouny killer?"