FE chassis numbers are usually on the passenger's side, in the area you mentioned. They are often stamped on the convex curved surface of the inner guard, which can make them very hard to find. Especially as the numbers are only about 3/8" tall, unlike the FC and later ones that are closer to an inch high. Feel along that curved edge for them, and try rubbing some talc on them if you can't read them (this doesn't work on india ivory inner guards
)
I've got two FEs, one from Sydney and one from Melbourne. The Sydney car has the numbers back near where the regulator used to be, but the Melbourne car has them about the middle of the battery box. In both cases they're on that curve I mentioned.
Hope that helps.
RET