This date is borne out by the Angelology of the book, v.
"Introduction to the Old Testament"
John Edgar McFadyen
His language shows a spirit of impatience with this elaborate Angelology.
"The Expositor's Bible: Ephesians"
G. G. Findlay
Moreover, there are features in the Angelology of Hermas which strengthen such an argument.
"Landmarks in the History of Early Christianity"
Kirsopp Lake