Per my experience, your's would be the first and only indication of such breakage, for a Makarov. Grain refined hardened steel materials can be, and regularly are, tough, easily well within the service requirement for a firing pin.
Are you saying the firing pin of the Rohrbaugh is a stainless alloy, 17-4 PH perhaps? Typical hardness for the treated material is 450-500 HV10, which is softish compared to [generic] tool steel. Or may the aluminum alloy frame be the material contraint against dry firing, w/o a snap cap? Does the manufacturer's literature indicate anything about this?