No, there is a small difference. While they both wear the same maid costume and shoes, their hair is different. Rem has blue hair and Ram has pink hair. Their haircut is the same. If you want to cosplay with two people, where one of you is Rem and the other is Ram, and you think it is a bit boring or unoriginal that only the wig is different, an option is to play the sisters before the attack on Oni Village. In that case, you can play Ram with a demon horn. This horn was cut off when the demon village was attacked, and she tried to protect Rem from the Witch Cult.