Not to be overly nitpicky, but this is a phase II E7. The spotting features are the roof vents in lieu of fans, the lack of a continuous filter grille along the side, the vent compartment behind the door, and specific to a late phase E7 are replacement of paired windows with vents. Much like the F3 built during the same period, the E7 was an evolution of design specifications that changed quickly from the E5/6 prewar locomotives to the E8s of late 1949.
As for the screw, have you tried looking at the brass screw section at Ace Hardware? I have found more than one good match going through the miscellaneous bins of brass screws. I believe Overland imported a lot of Ajin product. The trainphone antenna gives it away as a PRR prototype.
A great find! Enjoy!