Is smoked flavouring of bacon pieces gluten free?

The answer is: it depends

Gluten is a protein found in wheat, rye and barley. Smoked flavoring itself does not contain gluten, but it is possible that the bacon pieces used in the flavoring may have been processed in a facility that also processes gluten-containing products, or may have been cross-contaminated with gluten-containing ingredients. It is important to check the ingredient list of the smoked flavoring to ensure that it is gluten-free. Additionally, it is important to contact the manufacturer to confirm that the bacon pieces used in the flavoring have not been processed in a facility that also processes gluten-containing products, or have not been cross-contaminated with gluten-containing ingredients.