Yes — it's a feature we call BYO ("bring your own"). Once your space is twinned, you can bring in pieces you already own so your design reflects what you have. Your $49 covers unlimited BYO items.
You can add an item from:
A photo of the piece,
A link to where it's sold online, or
An upload with basic details.
Items you add are recreated from the info you provide, so their size, color, or finish may not render exactly — typically a looser match than catalog products. Use them to plan the layout, and check the real item for precise dimensions.