my pentax 67 (not ii) will not fire w/o film in it. or usually not, as it's not designed to, but every once in awhile I'll notice it will until i open and reclose the back. it will wind w/o film though.

needless to say, i've found they're a camera that tends to have a lot of personality as they age... buying used ones is not as safe as buying a used hassy.