ASC did a lot of installations like that back in the day. They were pretty good at it. Sometimes the car makers had arrangements with them so people could order stuff and the factory would take care of it all (make the car, then ship it to ASC for the specified modifications), and other times dealers would work out their own arrangements outside of the factory process. Probably the way to find out would be to get the PHS documentation and see where the car was shipped to when it left the factory.