For some strange reason (known only yo himself) Theo Walcott has changed his autograph. Upto last season it was long and thin in style, whereas now it is more like a report from a earthquake station, so watch out.
It also happened a season or so ago with Patrice Evra of Manchester United again he changed his signature.
When buying either of these autographs expect standard autographs for Theo up to the beginning of this season and the new from then on, Patrice is from mid time last season.
Hope that helps