That's a pretty good metaphor for the difference between genomics and proteomics.
I think it would be extremely difficult to study one without it relying heavily on knowledge of the other. But it would depend on the aspects you were studying. You could concentrate on the interactions between proteins for example, after they were produced, and that would have less to do with genes.
Or, you could study variations in genetic patterns without looking at the proteins they are coding for.
But generally, and certainly in the study of functional genomics and proteomics I think you'd have to take them both together.