as far a I know, not necessarily and for sure not if this is occasional transient trembling. Parkinson"s tremor is definitely "rest remor' meaning it is not related to straining fingers or it is not do called intentional trembling when hand trembles before any action. but it is constant, very specific, fine trembling, and the fingers are 'coin counting'. usually (as far as I know from reading) is is accompanied with prominent arm stiffnes and the whole hand has quite specific diagnostically meaningful look. Any neurologist can recognize it becuase it is very special in appearance.In BFS and even in overall healthy people it happens sometimes that the fingers can tremble on their own. Our involutarily movenents range includes such movements too, but they are ususally not so specifically organised as in PD.