Like you, I built one may years ago, I will try to make a better job of this one.
Why they label it F/G I have no idea?
The G had a completely different wheel arrangement.
The F was the final model of the normal II series and 524 were produced from 1941-1942.
A lot of the delayed production was used as a chassis to mount various guns on.
The Tamiya sheet says it had a crew of 5 - wrong, it was three surely.
As far as I can make out this was first produced in 1971, the version I have actually has an opening for a switch and a place for batteries.
Considering the age the parts are crisp, they do feel a bit clunky compared to more modern offerings.