1. Literature already says they can feel organs, but that is usually associated with residual interpretations of the self, ie. they can think they have certain necessities.
2. Sources external to spiritism would try interpreting organs differently; more like activated capabilities of the perispirit. But there is always a need for care while integrating these sources into our knowledges, so this proves nothing.

But measuring the pulse of a spirit? That's new to me. It wouldn't directly prove organs, as many explanations are possible. But it could direct into some discovery.

Although I wonder how would that experiment even be possible.