Even though the colours are more vibrant on the second one there is no difference between this banknotes. Also P-77 var. is a false reference, when will people stop making up those numbers…
For these sorts of things the online Oxford university image comparison tool is very useful. These two notes came up in a conversation I had with a colleague at work recently. The image compare tool is the best way to find differences because it allows you to save a toggle comparison as an animated GIF.