The obvious difference, beyond the fact that yours has a mirror finish and the one in the Numista photo does not (maybe it's just the photography, but it looks as though someone has been at it with a wire wheel!), is that yours is 900 fine, marked as such with an indented stamp, but the one in the Numista photos is 917, marked in relief without indent. Frankly I would be more likely to regard your specimen as trustworthy.