Is a 750 gold stamped ring real gold?

Yes a ring with 585 or 583 means 14k (which is 14 parts gold and 10 parts another metal.), 750 stamp means 18k (which is 18 parts gold and 6 parts another metal.),417 is 10k (which is 10 parts gold and 14 parts another metal.), and 333 is 8k (which means 8 parts gold and 16 parts another metal.) It is just another stamp system used mostly on items of European or Asian origin.