Regarding the orginal Joust artwork on my cab vs. the vector images at localarcade.com, I found a number of differences, most fairly minor. The shapes of a number of objects in the original art were different than those in the vector files - varying up to 3/4" in some cases. As an example of a larger difference, the eye of the ostrich mount in my original artwork is at a completely different angle than than of the vector art.
Overall, the vector art is very close to the original, matching in many instances, but different enough for my purposes of as close to a 100% restore as possible, that I opted for the the hand stencil. That is not a good economic and time decision, as the vector art would be much faster and cheaper to use than hand tracings of the original.
I have not idea why the differences exist. I am guessing that they may have been some variation in the stencils used for the original Joust art over the life of its production.