Are Airplane Maintenance Guidelines Insufficient?

In 1990, British Airways Flight 5390 lost a newly installed windscreen causing the pilot to be sucked halfway out the window. Two crew members secured the captain while the copilot was forced to take a risky maneuver landing the aircraft. In the aftermath, it was determined that the shift maintenance manager had failed to follow protocol to correctly identify which bolts were needed. At just 0.026 of an inch in diameter too narrow, the bolts were insufficient to support the forces exerted upon the windshield. Although the manager clearly violated protocol and several recommendations were made to avoid a similar mishap in the future, a critical safeguard appears to have been overlooked. Given the nearly identical appearance of these bolts and possibility that the correct bolts could still be put in the wrong bin, why take a chance on bolt size or labeling errors? Sometimes product codes are hard to read particularly if the font is not the best choice or printing is too light. If the ends of the bolts each had a distinct color or even better, pattern, this would reduce the chance of misidentification. Grant it, it would be problematic if the person were color blind. However, the pattern would still be discernible and color blindness could be screened. Why anyone would manufacture nearly identical parts without utilizing every possible method of distinction makes no sense to me. Moreover, how could something this crucial be entrusted on a single person? A second quality control officer should always be required to sign off on materials used and how work is done.