By chance and happenstance is where they are found. Sometimes on the classifieds here, sometimes on Gunbroker, sometimes on E-bay, sometimes at yard sales, sometimes at auctions, sometimes at high end on line gun auctions. The Pre 27 would have been in the Gold Picture box, and correctly sized and marked for the correct size of the gun. A particular marking on the back of the box in grease pencil would most often be the S/N of the gun that was in that particular box. When you find one it won't be cheap, depending on the condition of the box, from $250 for a squashed ratty box to $500 -$700 for a nice one.

Often times finding the gun you want is much easier than finding the box. Sorry I can't show you a picture, as I don't have one for my 3 1/2" Pre 27.

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H Richard
SWCA1967 SWHF244