There were 3 versions of the F1, If it has a matte black finish it isn't an F1n, it's an F1N which is a New F1 a completely different camera, different shutter , different metering http://en.wikipedia.org/wiki/Canon_F1 to the F1n which was an updated version of the original F1.
Right! And as log as the TO has not specified which Canon F-1 model we are talking about (old F-1 resp. F-1n [from 1971-81] or New F-1, often referred to as F-1N [from 1981-92]) all discussion is quite useless, because we are comparing apples and oranges here.
Canon FD &EF, Mamiya AF, Nikon, Pentax, Praktica, Minolta