No doubt, this is a genuine EG shoe and I see from AskAndy you acquired them for the enormous sum of $ 9.99. Congratulations.
The shoes might even be older, in EG’s catalogue of the late 80s, they are featured in the ‘new’ style with added facings. (Only from pejsek’s pictures did I become aware of the old style.)
Don’t know anything about last 520, previous catalogues featured a last 505 “rounded toe with added depth for a more sporty look”. The 520 last is probably on similar lines.
The shoes might well be from the late 70s, before John Hlustik acquired the company in the early 80s. The factory should be able to tell you the exact date of production (assuming they have not totally got fed up with all the enquiries: “Found those shoes in thrift shop/eBay, what can you tell me about them?”
Again: Congratulations. Wear them in good health.
P.S. If they need resoling, let the factory do it.