Mormon missionaries are carefully taught not to knock more than three times on any door in East Asia because the word for the number 4 sounds the same as the word for "death" in Japanese, Korean, and Chinese, so the main character would not have done more than three knocks on any door.
No Mormon missionary would risk picking up a fashion magazine, especially in a place as public as a convenience store, as her companion or any passing Church member (particularly Japanese) would certainly have reported it. (Note that they can read them before and after their missions but not during their missionary service.)