The outside of the hat is smooth, and the reverse is the suede side of the leather. Mine was received before the new darkening tecnnique was employed, I'm assuming. They appear to have surface dyed the leather, which is why the underside is a different color. I've resolved that color issue much to my satisfaction, using the following methods.
I simply "aged" mine a bit on both sides using leather dyes, lots of water, and burrying it in my back yard for several days, then watering said burial ground. Upon removing it from the mud hole, I drug it behind my car through gravel and over rough pavement. After another good and thorough soaking in muddy water, I placed it upon me head to let it dry for a custom fit. Then I gave it a good brushing to remove the debris, and followed up with generous amounts of mink oil on both the smooth and sueded sides.
Though a mighty headache and muddy hair were the unfortunate side effects, a perfectly "aged" and well fitting tricorn resulted.
The headache has long passed, and I've washed me hair since.
I must track down the receipt, but I'm certain I purchased this tricorn from Excaliber.
Ye may be thinkin' I went to a great deal of effort to achieve the "lived in" look, and perhaps you're right. It's an art, this business of wasting time...