Looks like Luca is neither wearing a chest piece, used AI, or photoshopped the check out of her recent Tifa Pics.
If you look at the right breast, you can see that the suspender is floating off to the side and not falling naturally.
The shadow underneath it more is cut off and looks really out of place.
Texture of her breasts is too smooth and doesn't match the rest of her body.
Not really a fan of this approach as I think she's selling herself short having to resort to fakery to sell her images.