These two genera (some even say they are paraneetropuls now!) has a number of fish that look similar when young, and sexing them visually is pretty much impossible at this size. If you bought a group you can sometimes pick out the bigger males, still not 100% though. I think you're in the right ballpark with the species, but it's going to be hard to say 100% at this size. Grow them out, it's like a game where you don't know what you're gonna get! 