I have found that my non caramel amels fade as they mature. From what I've read of the caramels, they are supposed to have a more vibrant body. Does your friend know where s/he got them from? It would be easier to figure out if it's known where they come from.
If I'm not mistaken it was from Hardy Reptiles but she deals mostly in ball pythons so I have a suspicion I won't get much info on them. I do have an amel that I have no doubts being amel but these guys being overall brownish/caramel color I'm unsure. Newest Amel addition.
It's hard to tell on a lot of them but I've been told that Amels are more purple while Caramels are more brown. here's a couple pics of my amels for comparison. I don't own caramels so can't give a pic of them. Your's look more brown in all pics but the first but cameras can mess with colors a bit.