Buckskins also have black mane and tails the buckskin body coloring is from a dilute gene however the dark points ( black mane/tail, legs) remain. As you can see from the picture I posted in my first response. Misty is Buckskin her tail, mane legs are black. Although as with most horses with any black coloring it gets sun bleached and appears to be dark brown or a reddish brown
Lp, the appy gene, is very well known to mess with colors. And it especially likes to put white hairs in the mane and tail. Some it turns mane/tail to completely white. The other thing it loves to do is change leg color.