There are some coordination compounds like $\ce{Na2[Fe(CN)5NO]}$, where ligands like $\ce{NO}$ are used which exist as both $\ce{NO+}$ (nitrosonium ion) and $\ce{NO^.}$ (neutral nitrosyl). How to identify which ligand is being used in such complexes?

A similar question was also on Quora but none of the answers were satisfactory.

Please don't answer with respect to Raman/infrared using stretching frequencies etc. since all that is out of scope at the level I'm currently studying.