This here seemed to confuse a few, but not all.
The AVLB (Armor Vehicle Launched Bridge, M60 Chassis) was often stood "up" just to make life easier for the crew to work on the launcher, which was sometimes parked inside for work:

When deployed it looked like this:

Animated .GIF here. (about 1MB, wait a few secs for it to start. To stop on any frame, click the browser stop botton. To restart, click Refesh.)
As for the gun. Here's the carrier:
Z'at help? ;-) --SangerM

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