Yes, specific holo cards will have a ditto underneath them. In the bottom left corner of the card, there will be a small ditto indicating that the top card is actually a ditto and can be peeled off.
Source: https://youtu.be/_JotwkYHDhU?t=457
I believe later in the vod it is also mentioned that the only three cards that can have a ditto in them are Numel, Spinarak and Bidoof, although I don't recall. What I do know is that it's definitely only those three cards that can contain ditto.
