The same colour will print differently onto coated and uncoated paper. If your colours look duller compared to a previous job, it may be that the job was printed on a different paper stock.
To ensure the colours on your printed work are as accurate as possible, always select colours for your artwork from a Process / Solid to Process Pantone book. If you have done this, consider changing the paper stock to give more vibrant results. For example, uncoated papers “dry back” and produce slightly duller colours than coated paper.