As randr21 mentioned, it looks like a cousin of a nightingale. Very apt description.
I'd add, that it looks like the nightingale's plain-looking cousin, however, lol!
In all honesty, if you like it, then you should get it. Have it authenticated first, though I doubt there are many fakes of this specific bag around.
May I ask a question, though? Are you buying this because the price is cheap? If so, I've learned that buying a cheap alternative will not eradicate the lust for the more expensive option. But, if this is what you want, and not an actual nightingale, then go for it and enjoy it in good health
If a nightingale is what you want instead, save the $500 you'd spend on this, give yourself sometime to do some more saving and take advantage of the next sale season to find yourself something closer to what you want.
*gosh, me and these long responses, sorry*
Good luck!