Do you have a picture of a JDM Camera on a Legacy? I'd like to see that, since I've never seen one. I did a quick search but couldn't find one.
Or even just a Part#, so I can check the Parts diagrams?
Is it like the picture below from a WRX? They're very boxy and stick out surprising far.
I guess my one that I bought online from an Oz Electronics store sticks out just as much (picture below), just seems a bit more streamlined since the housing angles down.
But I see what you mean about the blanking plate, is this it (or the similar one on the other side)?
Mine is a solid piece and needs to be cut out, but I can see where it'd go.