User blog comment:FairyRaven/Fairy Tail Chapter 333: Man and Man, Dragon and Dragon, Man and Dragon, Review and Commentary/@comment-5105419-20130603035234/@comment-7418318-20130603060412

Natsu got the scarf from Igneel, so it's possible that other (past) Dragon Slayers got similar presents from their teacher.

Thus the scatf alone is a very weak indication of it actually being a depiction of Natsu.

Also the only time Natsu ever wore a hood was in Edolas, when they tried to "conceal" their identity.