Is this Hayden Harnett authentic??

Looks right to me. Are you aware that you cannot safely use the side compartments? Even a tiny slip of paper I put in fell out. The problem seems to be a combination of: a) shallow compartments; and b) weak magnets. There has been a great deal of discussion about this on various threads. If that doesn't matter to you and you buy the bag, enjoy it! If it does matter to you, don't buy it.
 
I love my Mercer 3C - not had any issue with weak magnets and falling out papers. I find the side compartments quite handy actually - I toss my HUGE mass of keys into one side and tuck my driving gloves into the other and I'm good! No fumbling around for anything! My wallet on the otherhand stays secure in the center compartment. I have forgotten to zip it many times, and have never had an issue with it falling out either.
Just my 2 cents! :smile: