There has been much discussion on the fact that service and Magna grips are numbered to a specific gun, while targets and cokes rarely are.
Some light may be shed on this (hopefully Roy will chime in) in Roy's commentary on the manufacturing process.
In his commentary a raw frame is fitted with a yoke and sideplate and sent to the stocking department. If I read correctly once stocked the frame and grips are numbered and sent off for the next stage of production (built to a specific model?).
The question is were all guns stocked with a numbered pair of grips, but when the finished product was ordered or spec'ed to have target grips were the numbered grips discarded or when a surplus built up put on guns with different numbers?
In a couple of ways this would make sense. #1 is each frame size shares a block of numbers amongst the models within that frame size. At the time of yoke/stock/sideplate fitting the gun is just a frame size and not a model yet.
#2 we all know of guns that are apparently unmolested, yet have grips that number somewhat off from the gun. In some models like the 520...that is the rule, while others it goes outside the norm. I think we get complacent with thinking that some owner changed the grips at some point.
Here the question bares asking...why would some owner replace what came from the factory with the exact same grip with a different number. I know it happens now when we acquire a gun with the wrong grips (usually aftermarket), but is that same explanation true of guns acquired closer to when they were new?
Is there floating out there somewhere sets of Magna grips that number to my Pre-29's??