BNT Canada Mystery Hammer

From a reader come these pictures of an unusual hammer with an oddly slotted and wedge-shaped head.  Although it's proportioned like a small tack hammer, it's a substantial tool, with a double head 8 inches long. The faces seem to be angled to facilitate tapping using wrist action. Comments to the Duke's previous  B.N.T. post seem to indicate the company made different types of hammers, this one must be for a specific and as yet unidentified purpose! Any ideas?