No, CBD (cannabidiol) is a compound defined by its chemical characteristics distinguishing it from all other compounds in the physical universe. Any suggestion that CBD derived from hemp is different from that of marijuana is false. This would be akin to suggesting that calcium derived from a cow’s milk is different from that of a goat. It is less contentious since hemp and marijuana are slight variants of the same species.
The final CBD extract from a hemp cultivar may indeed differ from that of a marijuana strain for features such as terpene and cannabinoid profile. However, these characteristics will also distinguish different strains of marijuana since they have been selected for other attributes (e.g., %THC). There is no reason that a hemp variety could not create a CBD extract identical to that of marijuana, differentiated only by its low THC content.  The quality of marijuana or hemp may vary, but the essential compound of CBD remains.