Well Rob, to add a bit more to your confusion... there is a difference between early BJ7 and late BJ7's. I discovered this in the same way we all "discover" many things about our treasured LBCs.
If you have an early BJ7 (I don't know the breakpoint for these differences), the arm that lifts the window up and down is relatively straight. The later version has a bend in it a few inches from where it fits into the channel that it slides in when raising/lowering the window. The bend helps relieve pressure from the slider. The earlier (which mine had) straight arm puts considerable pressure on the slider and can fail (guess why I know). I replaced mine with the later version and now the windows work great.
Another, early/late BJ7 difference can be seen on the upper edge of the window channel. The early channel is solid all the way up (that's the chromed portion of the channel). The later version of this channel has a notch cut out of it (same as a BJ8). The notch gets filled with a little rubber bumper that is attached with a machine screw. On the early BJ7, solid channel, the ENTIRE window and mechanism must be installed as a single unit... try doing that without breaking at least one of the little nylon channel guide!!