Are you certain? From the camera angles in the films I dont think I could ever tell a 100%. I've certainly seen it written about Gamera that flames come from his limbs and head, but was that just from writers making an observation? Or was it from the film director or FX guy?
Plus, it would make more sense than from the limbs... but then again, Gam probably has a tube system to funnel it to the limbs. Cant explain the spinning though. lol