hard to tell but since you happened to ask right at 4.20 I have to respond with something...lol
First I agree with Adhlc in that Rams are hard to sex when young. The best way to tell that I know of is that the males generally have a taller spike at the very front of their dorsal fin. Look at the last pic in your first post and you can see the extended tip on the front of the dorsal fin. that guy looks like a male to me. the females generally dont have this extended tip. females do however tend to have red/orange bellys but that doesnt come until they mature more so you probably won't see that just yet. It's possible the one in the pic in your second post could be a female but its hard to tell. so many times ive tried to sex them when young only to find out a few months later i got all males...lol
hope that helps...