Ruddlesden-Popper nickelates have attracted intense interest following the discovery of superconductivity in several members of the series, including bilayer La3Ni2O7, trilayer La4Ni3O10, and structural polymorphs composed of monolayer-bilayer or monolayer-trilayer (ML-TL) units. A comparitive Raman spectroscopic study on the various Ruddlesden-Popper nickelates and their polymorphs reveal distinct phononic signatures for each phase which acts as a non-destructive method to identify the stacking order even in intergrown crystals. Moreover, electronic Raman scattering exhibits polarization specific features at lower temperatures, likely associated with the spin- and charge-density waves observed in these systems.