An exact date is pretty tough to pin down but I think they started making these in the early 80s and they came with a nylon pouch/belt sheath.
Here's the 1984 Kershaw Catalog which includes the Black Horse. They were originally made in Japan and later production moved to the US. Hoffritz was a brick-and-mortar chain store at one point and it's not clear whether the manufacturers applied the branding for them or if they did it themselves upon receiving the knives. Cold Steel, Kershaw, Buck, Victorinox, and Spyderco (to name a few) knives can all be found with that Hoffritz marking.
Hoffritz is still around, it is possible that they could give you more information. They have a small banner at the bottom of their home page with pictures of knives sent in by customers.