Could it be? They look pretty very real.

Oh, I like this one, I mean these two. 

All the items in this photo look pretty real.  One can clearly see her breasts rise from her chest and fill the lace cups of her bustier.

The cleavage shading looks very true to life and even this close up appears to be real instead of makeup shading.

The darken areola of her breasts can be seen through the lace of her bustier.

I was there when this picture was taken (you have to know your subject to get this close) and I can assure you that those aren't two silicone filled breast forms you see under the lace of her bustier.