Have you seen the two movies: "The Good, the Bad..." and "Once upon a Time in the West" ?
Sholay is not a rip off, but there are some similarities.
Btw the "Once upon a time" movie series, "The Good, the ...", "Magnificent Seven" and several other Hollywood movies of that era, were either rip offs of, or heavily influenced by the works of Akira Kurosawa, a Japanese director.
This guy was a giant. And his movies like "Seven Samurai", Rashomon" " Kagemusha", "Yojimbo" are true epics.
A lot of copying is done by Hollywood too, without giving credit were it is due. A recent example is Martin Scorcese's movie "Departed" (starring dicaprio) which is near identical copy of Chinese movie "Infernal Affairs" part 1. No credit was given to the Chinese movie. PS: The Chinese movie was way better; it gets better in parts 2,3.