It depends. What state did your wife hunt when she hunted? Did she complete a state-sponsored hunter education course? If so, many states, including Idaho, keep student/class records going back to when hunter education became mandatory.
In Idaho, all hunters must show proof that they have completed a hunter education course if they were born on or after January 1, 1975.
Depending on what can find out, she may be required to complete an Idaho course. For hunter education course options, please refer to page 100 of the 2012 big game regulation. You can also contact your nearest IDFG office for specific details.