Here's the link to some hoof shots on the Pete Ramey website that should give an idea of what the Mustang roll is. natural hoof care
It is not something every trimmer/shoer knows how to do.
I have been trimming off and for 49 years. When my 21 yo TWH became metabolic a year ago, I took everyone's hooves back.
I found a Pete Ramey student 40 miles away who willingly spent the winter mentoring me on my own four horses, so I could learn to utilize these new (to me) trimming principles plus manage my metabolic horse's hooves.
I am still skittish about using the agressive roll like he wants me to on the one horse, but I have conquered the degree of roll he wants me to do on my metabolic horse.
It is the best thing I could have done for this horse. My metabolic horse will probably always be laminitic but he has never foundered. I give every credit to his fairly ouchless movement across the stones in the paddock to the barefoot farrier's teachings.
That being said, common sense will dictate that I put boots on Duke if I ever take him off our property, but the fact that he can "hit a good lick" (he's a Tennessee Walker) coming across the stones thru two gates without gimping is a wonderful sight to behold.
So yes, there is a lot more to the "natural trimming" principles as opposed to the pasture trim that most shoers do.
Typically a natural trimmer will not put shoes on a horse. If the shoer professes that he does "natural barefoot trimming", I would ask him who he studied with and then check those credentials to be sure.
My current barefoot farrier/mentor USED to shoe. He became disenchanted with shoeing methods that weren't helping the horses as they were supposed to.
He studied Pete Ramey's principles, and after three years of practicing on his own horses and any friend that would agree to keep their horse barefoot, he felt he was finally ready to "go out in the world".
He will tell folks if they are not happy with the barefoot trim, it is their right to go back to shoes, just don't call him
I hope I helped answer the question some