No, the query syntax is not correct.

See https://javadoc.io/doc/org.apache.tinkerpop/gremlin-core/latest/index-all.html#I:V
and you not that V() exists for both the GraphTraversalSource, the GraphTraversal and for __.

Look again at https://javadoc.io/doc/org.apache.tinkerpop/gremlin-core/latest/index-all.html#I:E
and you see that E() only exists for the GraphTraversalSource.

In other words: a mid-traversal E() is not allowed and you get the error that more or less says so.

Best wishes,     Marc