windweaver77 
I thought I already commented on this but here it goes again.
The coin is a Contemporary Circulating Counterfeit. It is not a Numismatic Forgery. I own 12 copies of this fairly common variety. Only one is in a higher grade than this particular coin. Of the 12 there are 6 examples with a medallic rotation and 6 with a coin rotation.
The coin is NOT silver at least not the 12 I own. Eleven are German silver (white metal) types and a single example is struck in copper. The eagle design is old and very closely related counterfeits of other dates are known.
The 12 copies I own were purchased after I started using
ebay (ca 2000 on). This counterfeit was not at all common in New England. Only one example, the copper strike originated in New England.
The price paid is actually low given the current market. If the seller ever wants to sell the coin I would bid on it.
Also it is not the only D dot coin made either. There are a few of them. There are also D with no superscript and Ds. Fantasy mint marks are always interesting.
The ping test to determine silver content is almost entirely worthless. Other metals can fool an untrained ear. A far better method is a density test. It is easy to do and has a valid scientific basis. Density tests are not fooled by clad coins. A 903 fine silver coin has a density of 10.31 grams per Cubic centimeter.
Many of the counterfeits of Mexican 8 Reales were clad varieties. The earlier types are Sheffield plates while the Second Republic counterfeits are virtually all electroplates. German silver counterfeits are normally common because no one ever bothered to melt them since the component metals were worth almost nothing. Silver however could be reclaimed by refining or by using mercury to remove silver electro-plate.
The 1840 D dot variety is struck from engraved fantasy dies and is edged with different patterns. The edges still need some study. Edge typing is very difficult because of the very limited ability to compare the entire edge on each coin. Too many are worn or damaged to even allow basic comparison. The edge on this example seems to be the same as the high grade example I already own.
I hope that helps. Any questions please ask.
I am working on a final cataloging of the counterfeit Cap and Ray 8 reales that I own or have seen - in anticipation of producing a catalog of varieties. It is a daunting task since I have close to 7,000 Cap and Ray 8 Reales and fewer than 1000 are genuine. In addition I have 5,000 photos of counterfeits I have seen on
ebay or other venues. I am still hopeful that I will get access to one other very large collection.