You could. A friend of mine bought both the mask and the coat. When the mask arrived, I was a bit surprised that it was made of felt and burlap. The hat was a separate piece made of felt and had straw hot-glued inside. Most of the straw had broken/fallen off by the second time he tried it on. There was nothing inside the mask to protect your face from rubbing against the burlap, and it was almost impossible to see out the eye holes. It was very simply made and I honestly felt that he spent at LEAST 300 bucks too much. It was almost embarassing.
I replaced the straw with some synthetic stuff that looked the same, but didn't break or fall out, and I took an old Mexican-style wrestling mask and hot-glued that inside so that it could fit to his face, let him see out the eye holes and not itch like crazy!
The coat was also felt, which may or may not have been historically authentic, but either way, was a better buy than the mask, although still too pricey, as far as I was concerned. The coat was very clean, but the instructions did suggest ways to dirty it up (we used spray paint, as we wanted it to last) and pointed out that the bird droppings were "optional". We added them, using acrylic paint.
After buying the mask, coat, shirt, pants, boots and gloves, I'll admit he did LOOK good, but he'd spent almost 2000 bucks! He ended up wearing the costume at Wizard World Chicago last year, for all of about one hour.
One warning... if you do make a costume, I strongly suggest you wear it enough to get used to it before wearing it in public, to a party or convention or whatever. That wooden cross-piece in the shoulders will smack into everything and everyone till you get used to it, and it hurts! I had bruises to prove it!
