^^^^^^ Funny stuff. I actually saved those graphics as a potential reference. Lol.
They also carried codes that match 355th FG planes. They were not attached to either although some of the pilots did come from those groups. They also were converted bomber guys flying them.
I am reading in one spot that the 1SFX used 5E. Another place says they used underlined versions of the main code letters YF, OS, and WR (355th FG).
It SEEMS though, that they inherited some 364th airplanes based on some crackup photos. Still, this could just be confusion. It’s amazing how many 5E photos cover up the exact spot I want to see.