Looks authentic to me. The spots could be corrosion spots, alloy inclusions, or surface contaminant like glue or paint.
You could check the weight if the holder can be opened. The coin looks BU and should weigh very close to Morgan dollar specified weight of 26.73 grams.
You could check the weight if the holder can be opened. The coin looks BU and should weigh very close to Morgan dollar specified weight of 26.73 grams.






















