All US Coins are graded on the same numerical scale numbering from 1 (lowest grade) to number 70 (highest grade). In theory a coin graded 1 would be the worst possible example of that coin and a coin graded 70 would be a perfect coin. In reality coins are graded on a scale generally as such from lowest to highest.
G-4, VG-8, F-12, VF-20, EF-40, AU-50, MS-60, MS-63, MS-65
There are many other grades between these numbers as there is no "forbidden" or "allowed" numerical grade as long as it is between 1 and 70. I suggest buying the Red Book of US Coins for a better explanation of grading.
A U.S. silver dollar dated 1892 would be a Morgan dollar. Your description of the reverse as "180 grades" means nothing in numismatic terms. Please post new question.
The 1886 Morgan is common and valued at $17.00-$26.00 in circulated grades.
The Morgan silver dollar is a collectors item and can be about $39
An 1879 "Silver Dollar" is a Morgan dollar.
A Morgan dollar IS a silver dollar. The term Morgan refers to the designer George T. Morgan who created the images used from 1878 to 1904 and in 1921.
Neither. The Morgan silver dollar is 90% silver, 10% copper.
Retail values are from $40.00- $70.00 for MS-60 to MS-63 coins which are the most common grades for a uncirculated 1891 Morgan
A Morgan 1882 Silver Dollar has 0.7735 of an ounce of silver.
The most common type of 1878 Morgan sells for $17.00-$30.00 in circulated grades
coz it ain't a Morgan silver collar
George T. Morgan
The 1881-S Morgan dollar is the most available of all 19th century Morgan's in MS-60 or higher grades. It has average retail values of $45.00 in MS-60 an only $65.00 in MS-63 which are the typical Mint State grades for this Morgan. Usually this coin is very sharply struck, an a great coin to have for the value.