The 1911 was not designed as a target gun. For it's original purpose, sights were a pretty low priority - and it shows! Notch was just too damn narrow.
If you have good eyes, they are just barely adequate. If they don't suit you, change them. It isn't a big deal to do so.
I have a pre WWII 1911 and the sites are lousy. Too fond of it to change them so when I shoot it, just live with it. I have others with good sites. That old warhorse sent more than one German to his reward. I have no doubt it would do the same, at close range, for any moron foolish enough to try and take it from me.