Eigenform product identities for degree two Siegel modular forms

It is known via work of Duke and Ghate that there are only finitely many pairs of full level, degree one eigenforms f and g whose product fg is also an eigenform. We prove a partial generalization of this theorem for degree two Siegel modular forms. Namely, we show that there is only one pair of eigenforms F and G such that FG is a non-cuspidal eigenform. In the case that FG is a cuspform, we provide necessary conditions for FG to be an eigenform, give one example, and conjecture that is the only example.