DPM Fed Ups Freight kit

[Lester Perry]

I believe the design of the building is probably 1940s or 1950s. Trucks were much smaller then. With that in mind you might try to figure out how the clearance problem might have been dealt with in real life. Possibly lowering the pavement to allow for the clearance. Your bricking the bottom and adding the dock plate is a good idea. The length of the trailer could also be an issue in reality. I don't know how much detail you are looking for but a dock lock would be at any UPS or FED X dock.