Hi
Mechanic ,I don t really agree .
There are 3 master version of FOK with 3 different doors.
The first version: gooseneck with square windows and small casting : metal frame door with wood center panel
the second version : Gooseneck with round Windows(bull eye) and large casting :Full Metal door with "wood paint" on it .
The third version : Escalator ,Silent model ,eagle on Front : Door with Brown paint .
All 3 have the same size! Inside: 19”1/8 X 14”
If you want more info (in French, argh stupid frenchy ) look at this address:
http://retro-jackpot.fr/mills/f-o-k/f-o-k-des-années-20
Stephane