When the first NATO E-3A aircraft were delivered a couple of them had recurring AOA problems, left and right indicators consistently had the same disparity. After much head scratching it was found that during manufacture, the template for drilling the holes for securing the mounting rings for the interchangeable transducers had not be turned over when going from the left to the right of the nose, with the results we found. The men from Boeing came with their template, drilled the holes in the right place and all was good.
But this was 35 years ago.