This variety is 1  of 5 documented hand-made die counterfeit gold dollar varieties dated 1857. This die sinker used a later date associated with the Type-1 obverse portrait and reverse wreath design.  This variety is part of a counterfeit family whose full extent has not been actively studied, but I can say with certainty that variety 1857 'C-3' share the same obverse as this variety, and variety C-4 probably was made by this counterfeiter too as it has a Type 1/1 obv/rev.
 
Only a few examples of this variety have yet been documented and it is one of the nicer examples seen.  About 5-10% of the original gold plating remains, largely in the recesses of raised design elements.  The planchet is brass.  And the photography on this example does not do this example justice!