Its slightly difficult because we don't know exactly what you mean be "legitimate". Are you looking for WW2 flags? If so, the second one is definitely not a WW2 flag. Maybe it is from the post-war occupation, but not from the war.
The first one looks OK, but I have my doubts about the way some of the characters are written. There are a couple that look like Chinese variations of kanji characters: the name on the far left is 鈴木岩男 (Suzuki Iwao), but the 鈴 part looks like how the character is written in China. On the right side is a character that is supposed to be 出, but it is written as 屴, which I presume is/was a variant of 出, but somehow it feels strange (otherwise the age and the other inscriptions seem OK). Addressed to Kitakawa Fujiharu (other readings possible).