There are several aspects about the scenario you described that I find troubling. First (barring an emergency), the only people who perform surgeries/procedures on my animals are vets that I know and trust OR vets whom I've carefully selected for that purpose. "New" vets don't touch my animals except in an emergency situation. Even then, I'll question them closely about what's required and how they're going to do it.
Second, no vet performs any procedure on my animals without my explicit knowledge and permission. I once verbally smacked down a presumptuous resident who aspirated a sebaceous cyst on one of my females despite my explicit instructions not to touch it. (I knew what it was and had been watching it with our regular vet). More to the point, we were there for emergency x-rays as I suspected that my girl might be on her way to bloating. Fortunately, she only had a bad case of gas. The smackdown ("What part of 'do not touch this' did you fail to understand and where is your supervisor?") resulted in a written apology from the resident and her supervisor, which also included a statement that any consequences of the aspiration (e.g., infection, change in growth rate) would be covered by the practice at their cost. I don't mess around....
Third, x-rays (at least) are required to diagnose dysplasia. If there's no film, what on earth did he do? And, why would one believe his assertion? At best, the vet is blowing smoke; at worst, it's arguably malpractice.
Finally, as I understand it, training and certification are required to both perform and interpret x-rays diagnosing dysplasia. Does the new vet have either? If not, what does he think he was doing?
I'd have a serious conversation with the senior vet in the practice, wouldn't let the "new vet" touch my animals in future, and possibly take my business elsewhere.