Todd - I would have no problem attempting to make the attribution based on a direct comparison. I could also like to take a series of pictures and do a Specific Gravity to see if it matches the Riddell # 50.
"Riddell" refers to a book published in 1845 that illustrates all of the Counterfeit and real dollar and half dollar coins found in circulation in New Orleans between 1839 and 1844. The full title is "Monograph of the Silver Dollar, Good and Bad". The author was Dr. John Leonard Riddell who was melter and refiner at the New Orleans mint. He was also a professor at a local college. But his job at the mint was to melt and refine silver from worn coins and other foreign coins sent to the mint to be used to produce US silver coinage. He indicated in the book that he was melting an average of $ 50,000 worth of Mexican coins PER MONTH for this purpose.
In 1839, his first year on the job, he discovered that batches of silver were running on average at least 5% short on silver - after he adjusted for wear. He suspected that counterfeits were mixed into the coin batches. So he began a systematic search. His book is the result of his research. He lists 282 different counterfeit 8Rs and has a picture of each cast from type metal. They are very accurate pictures and capture great detail. This is the only contemporary work on forgery that illustrates the coins being forged in such large numbers. The results of his work also indicated that 90% of all coins circulating in New Orleans were Spanish American and that counterfeit rates varied from 1 in 10 to 1 in 100 coins. Either way that is a huge number of foreign forgeries that were being used in the US.
My hope is to expand his work to cover the entire interval during which 8Rs were legal tender in the US.