OK, so what does Muslim clothing look like and why would ISIS be dropping off copies of the Quran along the trai? On top of flashing a giant 'We were here' sign on what I assume is a covert act, I wouldn't expect Christians to casually toss copies of the Bible hither and yon and supposedly the ISIS fanatics regard the Quran even more highly than we regard the Bible.
Why were Korans found along the trail? Sounds like you might not have done much night walking in the scrub desert. People lose money, backpacks, phones, buttons off their uniforms, weapons, magazines, compasses, GPS units,,,, and yes,,, even their esteemed holy book.