No. Pencil does not offer custom model training, and LoRAs (low-rank adaptations, often called custom models) are not available in the platform. Any custom model trained previously does not appear in the model picker.
You do not need one. Current image models reproduce a specific style, character or product from reference images, with no training run and no waiting. There are two ways to use them.
Reference images in your prompt. Attach one or a few reference images alongside a detailed prompt and tell the model which qualities to carry over. For example: "Match the flat illustration style of the reference image, keeping the same palette and line weight." Models such as the Nano Banana family pick up style and subject from references with strong fidelity. This works wherever you generate images in Pencil, including agent chats, the Ads editor, Workflows and Sheets.
Style references in your brand library give you a reusable reference set at brand level that any image generation can draw on.
For the full technique, including style transfer onto existing images and videos, read: How do I generate images and videos in different styles?