The only thing that isn't jumping out at me as the '56 is the 'O'. Yours is pretty rounded on the inner bottom, and is thicker overall then what I would say with 100% certainty. Everything else looks good, but I'm on the fence with the 'O'.Upon further review, I'm saying, Yes! It's an FS401b. Good eye!
You can see what I was talking about here regarding the shape of the O (additional images match your coin though):
http://www.PCGScoinfacts.com/Coin/Detail/410434