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The barrels are clearly stamped "Made in Japan and Assembled in Korea",

Sounds like the gun that was sold here as the BSS. In addition to my Mirokus, I have 3-1/2 BSSs, stamped both Japan and Korea. No noticeable difference among them, except that the Miroku guns are trimmer and a bit nicer than the BSS. Why 3-1/2 BSSs? Because I cannibalized one of the 12s to make a 28"/30 " two barrel set for my Sporter. If anyone needs a BSS 12 ga action with PG stock, PM me.