The 1977 set Cowboys features two cowboys, one with a pistol, and the other with a rope.
The set features one of the earlier versions of the minifig, half traditional bricks and half minifigesque parts. More advanced than the first attempts, but still much different and much larger than the modern minifigure.
The rope held by the first cowboy appears to be a lasso at first glance, a common tool used by many cowboys to round up farm animals. However, I believe that it is actually a noose.
Lassos have a large loop by design, the large loop is necessary for creating the circling motion, and so that the lasso is large enough to fit over the desired target. Lastly, having a large loop allows for less accurate cowboys to hit their target.
Was this an intentional move made by The LEGO Group? It's no secret that many Danes are blatantly racist, but it would definitely be surprising to see such a blatantly racist image in a toy. One cowboy with a gun, the other armed with a noose. A small lynch mob chasing after a Black man.
There is no conclusive evidence, of course, but it is interesting. There are many toys that at one point seemed perfectly harmless, but under a modern lens becomes blatantly racist.