Nikon F Film Guide Rails (on Part 20FB1-2001)

Film Guide Rails Type 1

Body casting has 4 film guide rails of the same width all the way across.

Recorded body numbers between 6400492, 6401395 and 6401595.

Same as type 1, but 2 inner film guide rails have small extensions on the rewind side of the body casting.

Recorded body numbers between 6401475, 6401781 and 7450960.