I have a Horton 624 purchased new circa 1985, still have the box, papers, tools, and unused holster in bag. To the OP, the original Combat grips command a premium and it seems as though over the years a lot of the 624s I've seen in gun-shows have aftermarket grips and the dealer will get a quizzical look on his face when asked if the originals come with it. In any case, after I bought mine I shot it some, worked up some loads, and then for the next 25 years it did easy but essential duty as my office desk gun. A couple years ago I brought it home, shot it a bit, and now it's a safe-queen although I may shoot it again sometime.

I believe the reason they sold them with holsters back in-the-day was that there were so few 3" N-frames around that finding a commercial holster for them was difficult.

Fun, interesting gun. Enjoy.