I thought it would unscrew too, but according to the link that DWThomas so kindly provided (thanks!), it appears that the only way to get the front cell off is to take the toothed assembly off. I was afraid of that.
For now I'm just going to use the camera as it is, and try to remember to dry fire the shutter w/ my hand over the lens before taking any important shots. The shutter fires well and the speeds are good (except for 1/200, which appears to suffer shutter bounce), but because the aperture blades are a little sticky, the first time or two you fire the shutter it often runs slow.
Taking the geared parts off SEEMS simple enough if you mark them, etc, but the last few times I tried this on other cameras it was a disaster. On most cameras, like my old Rolleicord/Rolleiflex, you simply unscrew a lens element, clean the blades, and spin the element back on. Not so the Argoflex. What seems to be a very simple camera is actually much more complicated than it first appears.