Is that pic at 8-10 days old, or is that from the first couple days you had them?
I think its too soon to tell from the pic, but the personality you describe would have me suspicious too.
post a new pic in a week or so.
Yes you can tell even within a few days in some of them. Those instincts for me have usually been correct, but its sometimes hard to tell.
Post pics if you can.
ETA: i had a BO that had a comb and wattles twice the size of the rest, and she was twice the size but still was a she.
The Buff...