By the looks of the stamps it's unlikely someone would put such effort into stamping it with the several individual marks it has if it were not authentic.
I do see 3 letters which indicate a makers mark but cannot make them out, if you would like please clarify what the letters are & this will help us with IDing the piece.
The anchor is a UK mark indicating it is a Birmingham piece.
Often with pieces made in the UK single letters such as the "N" will give you a good idea of the year in which the piece was created. The "18" indicates it's 18 carat gold and if it is a crown before the 18 it would indicate that it was made prior to 1975.
