I think you are correct, I had one of these and I seem to remember it originally being designed for the RK-740 fan with the engine inverted.

As I remember this kit was first offered from Zia models, then they either went out of business or were sold and it then became the Air Flare models F-86 (this is the one I owned). It is about the same size as the JHH F-86.
You might be able to tell if it is the Air Flare kit by looking at the inside of the glass fuse just above where the fan is mounted. Mine had a little peice of paper (about 1/2" x 1") molded into the fuse in this location that said "Air Flare models" on it. It could only be read from the outside, but if there is no paint on the inside of the model you might be able to see the paper from the inside if it is there.