The proliferation of AI-generated digital content has intensified the user demand for accurate provenance information to ensure content authenticity. Technical advancements now provide tools to make the digital media content supply chain more transparent through the use of provenance data. This paper foregrounds the importance of understanding how the situated nature of user-content engagement influences perceptions and uses of this data. Insights from a workshop with experts in the creative media sector suggest that, as the adoption of provenance data becomes more common, users need richer and more nuanced information. We suggest that analyzing the increasing demand for content authenticity through the lens of multiple "authenticities", each reflecting different user needs and contexts, can help identify and address the needs for, and uses of, provenance data by creators and audiences alike.