Big Block K Frame Identification

Ok guys round two. I need your help again. Purchased another K Frame that is supposedly a DC BB A-Body. See attached pictures. Iā€™m getting mount offsets of 3/4ā€ on the passenger side and and 1 3/16ā€ on drivers side. Inside dimensions of the perches are 3 15/16. Number stampings on the bottom are 452M401 and 453M401.

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