An old style passport should have two stamps in it. One shows the issue date; the other shows the expiry date. The latter is exactly 10 years, to the day, after the former. (For example, I've just dug out an old passport which was issued on 10/11/78 and expired on 10/11/88. I've also checked that the dates in my current passport follow the same pattern).
It seems that the passport office left the 'day' bit of their 'librarian's' rubber stamp set to a blank space when they stamped your friend's passport with the expiry date. However, the oval stamp below it should show the issue date; just add 10 years onto that.
Chris