Without knowing the specifics of this coin I can still say that it's probably a good buy just by reference to the bullion value plus age of coin and apparent good condition plus the fact that you don't see this coin everyday. Silk Road 1/3oz coins sell for $1000+ if memory serves me right.
The folks at Chinese Coins Forum (CCF) may have more information on this coin. Also search their archives in case the coin has been discussed previously.