Welcome to the brotherhood, Mike! As to your questions, the camera comes in 6x7 non-mirror lock-up (non-MLU), which is 69-75, 6x7 MLU, which is 76-89, then comes the 67, which was made from 1990 til mid-1998, when the 67II was released.
The shutter cocking key enables you to operate the shutter with no film in the camera, but according to "How to Select and Use Medium Format Cameras", it's best used by camera techs, as you can cause a problem if you're not sure what you're doing. You can do the same thing by opening the back, rotating the little knob in the middle of the film counter past '1', then closing the back while keeping the knob past '1' with your fingertip. This is something you typically do when you first get the camera, and want to familiarize yourself with the operation, and get used to the feel and sound of the shutter and mirror. If you remove the lens and trip the shutter, you can actually feel a breeze from that big mirror flipping up! If you get curious and remove the prism, the meter won't work until you remove and re-install the lens, in order to re-couple the meter. You're right, the viewfinder's not that bright, which makes the f2.4 and f2.8 lenses noticeably easier to focus than the f4 lenses. Now get out there and make some pictures! To test a freshly acquired camera, I'd bang off a roll and get it developed the same day, to be sure everything's OK, but maybe I'm just the impatient type. Happy shooting, Brother Mike! Brother Pat - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
