^Not to be a dick,but here's how to do it. Those pants could be VERY expensive,so this is what you do. Get any pair of plain back skinny pants....Make sure they're too long. That's it. If anything get them tailored.
That goes for 90% of the "Where can I get those ridiculously plain pants" questions.
I was actually talking more of like the texture on them. Y'know like how your average jeans look relatively rough or abrasive.