I am no expert in this area but I do know it is awful difficult to determine a coin's authenticity from a photo. Too much else needs to be determined. May I suggest you contact a person who specializes in the coinage of the Middle East.
I am not an expert on Sassanian (Reich der Sasaniden) coins, but I like to look for examples online. I found several like your coin. It looks like your coin is a recent unsold lot (at least the pics are the same). I noticed hints of over / double striking on the reverse of your coin. I found a dozen on line and see more weight variation than I would have expected for a gold coin (3.91 to 4.61 grams). That is a bad sign to me. The weight of your coin, 4.18) is near most of the examples.
This coin was ex Aurum Graecum collection. Its also listed under Sunrise Coll. Its from unsold list. That is why I wanted to get expert opinion, on whether to buy it One site says they are recent fabrications. Still the coin is listed in many reference books.... John
A further point. I hesitate to judge the color of a coin using digital images which may not be exactly what the color is so I could be dead wrong about this but this looks to me like a later gold alloy rather than the color of the kind of ancient coins I am familiar with. Again I urge you to allow someone who is an expert in Middle Eastern coinage to take a look at the coin. There is a gentleman residing in Southern California who is, I believe, a Persian, who advertises on the Net and has many Parthian and Sassanian coins for sale. You might try finding his site and sending this picture to him. Please do let us know what you are able to determine from your inquiries.
The overall style of that coin appears correct and the lettering look fine. This issue was minted in the 33rd and 34th regnal years of Kushru II and a similar example appears in Robert Gobl's book 'Sasanian Numismatics' (plate 14, #221).
