Nikon RFThis forum is dedicated to Nikon Rangefinders: the Nikon One, Nikon M, Nikon S, Nikon S2, Nikon SP, Nikon S3, Nikon S4, and Nikon S3M, Nikon S3 2000, Nikon SP 2005. Plus the ONLY production camera ever made in Nikon Rangefinder mount WITH TTL metering ... the Voigtlander Bessa R2S.
The closest rangefinder body to the F is the SP. They were coming off the assembly line at the same time for a while. Apart from the rangefinder vs. reflex mechanism the are pretty darn similar in build, but I'd be surprised if the backs are interchangeable.
The backs don't match . The F is 1/2" longer than the SP and obviously the viewing mechanism is different. Otherwise the cameras are identical . The F was delayed over a year because the engineers wanted to use the SP chassis but in the end they were never able to properly fit the locking mirror mechanism (the mirror housing had to be especially strong because of the 3 1/3 fps motor). Otherwise the F would have come out at the same time as the SP.
All this I got from this podcast featuring Robert Rotoloni (Nikon Historical Soc)