He did point it out to Graham, but he is gone. 🙁 It probably was an animal heart because if you think about Snow White the huntsman tried to use an animal heart to fool the queen but it didn’t work.
I am hoping it is Kathryn’s heart because what more proof would Emma need to see than a live person without a heart walking around. Graham told Emma it was the curse and brought her to the vault of hearts (well Graham’s guide).
All I know is that I am super curious and excited to find out how they are going to explain everything!