Is your question simply whether it is safe to replace the old LED with a modern one?
If so: it won't cause any harm (the higher Vf of the modern LED means it will get even less current than the old one did!). The only potential problem, particularly when changing to emerald green, blue, or white, is that modern LEDs can be so bright that they blind you! (In that case, you'd need to change the current limiting resistor to a higher value.) You somewhat see this in your pictures: the new LEDs are noticeably brighter than the LED display they're next to.