I have each of the "F"s. My mint .243 is the second from the bottom. I'd be hard pressed to let it go for billy's price.
Shouldn't there be a takedown, straight-grip checkered "F" in that picture to make it more complete?
I've posted about mine here before, and was told it was a rather rare model from the late 30's.
I'm honestly not trying to be critical, just seeking to expand my knowledge of 99's,
Old No7
We're off topic here OldNo7, but in answer to your question, no take down belongs in that group.
Your rifle is a 99F, take down, ~1920-1940's.
The pic above is 99F, solid frame, ~1950's.
If interested in going a little deeper into 99F differences, features, calibers, etc., getabookgetabookgetabook.