With no distinguishing features that boldly stand out to say "I'm a sandbar," this species is a close second to the dusky on the generic scale. Sandbars will vary in color from a bronze/gray to mostly gray and sport relatively large dorsal and pectoral fins. Like the dusky, sandbars are in the group of sharks classified as "large coastals" which signifies that they're more likely be found up on the Continental Shelf waters rather than out in the deeper water where the pelagic species are so common.
Sandbar sharks are a species that will often be caught in the surf and are known to frequently move up into coastal rivers and bays. In fact, the Delaware Bay is recognized as a nursery ground for this species, with the females entering the bay in early summer, giving birth, then heading back to sea, leaving the pups behind in an environment with less threat from predators.
Sandbar shark populations have been decimated after decades of being ruthlessly overfished by commercial fishermen for their meat and fins. Regulations are working to correct this tragedy, but considering the biology and slow reproductive capacity of this species it will take many more decades to rebuild the sandbar populations than it did to destroy them. The quality of sandbar meat is quite low and this species should always be released.
Color is not usually a good thing to use for identification because within a species the color of individual animals can vary a bit. But usually duskies tend to be more of a dark brown in color while sandbars will be gray or a gray/bronze. These color schemes tend to make the sandbar overall much lighter in color than the dusky, and when the angler finally starts to get the shark close to the boat the sandbar will appear gray and will be visible from the boat at a greater depth than the darker dusky.
A dusky is covered by minutely small and sharp overlapping dermal denticles and a thin layer of slime. Run a hand from head to tail down a dusky and it will feel slimy and very smooth, go the other way and it will be slimy but very rough. Do the same with a sandbar shark and the it will feel course in either direction because their skin consists of blunt, non-overlapping denticles, and no layer of slime.