Why don't you take what you learned about rendering here (since the shiny details are obviously what you fancied about this piece) and use that knowledge to polish up a piece you compose and draw on your own?
Then you'll have a piece you can have confidence in.
Frankly, if you even have to ask whether a painting is too much of a copy to legally sell, then you already have your answer. Even if it was borderline enough to be barely legal, do you really want a blatant copy to be the way you represent yourself in the art world? Nah.
'Cuz life is full of your regrets, and I should be one...