Well, at least when he was a schoolkid. This card with his sig turned up when a librarian was chucking some old volumes. (The book was a bio of Andrew Jackson.) At auction, this fragment of The King's youthful pursuits fetched a cool $7500. Below, Elvis in 7th grade, Tupelo, Mississippi. Just 10 years until Jailhouse Rock!! (A special edition, no less.)
Source:
http://dailyglean.salebooks.com/2012/08/elvis-presley-history-buff.html