No, no shims, it wasn't a common issue but it did happen on many Pinto 2.3l engines so I assume Rangers as well, some 2.3l went 500k miles without the issue others had chewed up distributor gears quite often.
Which would make me think it was something specific to the AUX shaft bearings or oil passages in certain blocks.
I would think the AUX shaft is moving, shifting positions, I think you would notice if the distributor bushing were the problem after removal.
If second gear went out then you now have metal flakes in the oil pan so flush it as best you can.
New AUX shaft and Bronze distributor gear(if you can still find one) would be what I would try.