Meaning, they could be a bad batch as a result?
Yes, that was my thought, but again, I think the pins look too clean for that to be the case.
Another possibility is that these are ones that failed the post manufacturing test (did they have automated test and scan testing with JTAG back then?) and were binned as failures, and again, somehow found their way into a sales channel.
A happier possibility is that these were manufacturing rejects, because their pins somehow got bent. So they are perfectly good chips, but couldn't be used in a pick and place manufacturing situation because of the bent pins.
Or they could just be left overs that never got used which suffered some pin damage over the years; e.g. someone spilled the tray onto a hard floor.
Leftovers do find their way back into the sales channel. AMD made the 79C950 (CURIO) for Apple, which is the chip used from the Q840AV through the PPC PowerMacs (x500 family) to provide internal/external SCSI, Serial, and ethernet. It was a custom job for Apple. Yet trays of those unused chips showed up on Ebay about ten years ago or so. I suspect that those leftovers were from one of the clone makers rather than Apple itself. Apple seems to do a "good" job of keeping its leftover chips off the aftermarket.