The skins from both are considered the most expensive in existence. The picture below shows alligator's wide round jaw - the caiman crocodile which actually belongs to the alligator genus also has this. The alligator has a jaw pressure of 2 tons. The crocodile has a more pointed design of the jaw. The first two have their teeth hidden, while the crocodile has poor dentition with many teeth outside and clearly visible. The crocodile is considered more aggressive than the other two. The horns on the neck have different numbers on the three reptiles. On the belly, the crocodile has a small dot in each shell (scale) which is probably a "sensor/antenna" that sends signals about prey below it. Alligators do not have this except under the jaw. If you find a women's bag with a dot in each scale - then it is the real deal. There are also differences between freshwater and saltwater crocodiles - not only in size but also other the sphincter in the throat. A saltwater crocodile can move between fresh water and salt water. Crocodiles are larger than alligators - an alligator is rarely larger than 10 feet. There are only two alligator colonies - the American Alligator and the Chinese Alligator. After 20 years of alligator conservation in the US - there are more than 2 million wild in Louisiana and more than 1 million wild in Florida. More than 800,000 are farmed. Crocodiles are commonly distributed in Asia and Africa and are in large numbers. The average age of an alligator is 40-50 years. Saltwater crocodile gets older - oldest approx. 70 years.
NB. The world's largest saltwater crocodile is Lolong from the Philippines, 6.17m and 1075 kg. The world's largest alligator was caught in Alabama in 2014, 4.90 m and 459 kg.
More about alligators and crocodiles at bredal-wild.com
Here you can see the difference between the horns on the backs of caiman, crocodile and alligator.
You can see the crocodile backpack here
https://bredal-wild.com/products/freshwater-crocodile-hornback
The Crocodile Bible has ISBN code 0-8160-2174-0