First off, welcome.
This type is one of the most reproduced coins of all time. Since the phonies run the gamut from contemporry counterfeits to restrikes to modern forgeries, it can be a complicated business authenticating these.
The edge is often the key to detecting spurious examples. Photos of that would be helpful, particularly any spot(s) where there appears to be overlapping of the pattern.
The weight you report is slightly on the light side. Whether its composition is correct can be determined by measuring its specific gravity for silver content, or even better through the more comprehensive analysis afforded via x-ray fluorescence.