Yep, pretty dodgy method in that video, Mike. I suppose, given the limited service life span that the GPW and MB were designed for, the method of preventing the pivot bolts from rotating was cheap, easily installed and sufficiently robust, so 'good enough' in the circumstances. I doubt the designers envisaged that MB and GPWs would be still employed by armies well into the 1960s, or that civilians would be trying to rebuild them nearly 80 years later.
There are possibly plenty of improvements that could be made to various parts of a jeep to make it more robust and longer-lasting. The chassis came in for some officially-promulgated strengthening while in service by the addition of 'T' pieces at the rear, and the steering bell-crank received an added web, for example.
Nice job on the bolts: very skillful.
Mike