It would of most likely left the factory in Springfield, Mass., in....

mid 1990 to mid 1991.

It's somewhat unusual for that time frame, but that s/n prefix was spread out over both years. May - June of 1991 is most common, but I've seen some marked May of 1990, too.

The features you describe make it sound like a product code 103618. This was one of the Classic Hunter series. Normally I see these with Hogue grips, but would not be surprised if some shipped with Pachs. Both were in common use in that era.

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~ S&W aficionado in training ~