Nothing real fancy Uncle Russ. I do prefer mesquite or osage thorns as they show two tone rings like endgrain of a tree trunk. You can use toothpicks and stain also.Prep is same as if you used a brad or nail, find appropriate drill and pre drill the holes, then melt you some beeswax and smear it on the plugs mortise that fits inside the horn. I use a heat gun for this so it good and soft while assembling.
If you can zoom in on that primer I posted you can see the end of that thorn and what it looks like. IMO, its the little details that can make a horn unique.
Thanks the positive feedback