I don't think it's a blackout hub Mike. If the last number is 10 then it's a heavy duty hub and would be correct for G519 military bikes and also service bikes and cycletrucks. These hubs had a Parkerized finish which has a dull sheen.
At some point during the war Morrow started doing the blackout finishes on next hubs to come down the supply chain. Shaun's example he has for sale doesn't note the date coding or spoke gauge. I have had three or four Morrow blackout hubs and they were all dated 45 and none of them had the 10 gauge spokes they were 13 gauge.
@Mercian