Rear window defogger

I’m helping my son with restoring his -66 Barracuda. Lots of rust, so far I’ve replaced front framerails, part of torsionbar frame, front floorpan, front leafspring attachment both sides, parts of the floorpan under the rear seat both sides, part of inner wheelhouse and wheelhouse openings both sides. Almost all of the repair are due to old sloopy repairs. Now to my question, its a fan with housing mounted below rear window on the passenger side, (I had to remove it to make some room for the welding of the inner wheelhouse) the housing for the fan looks like its ”homemade”. Could it be that it is made like this from factory?

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