I'm not sure where they put the serial number on the really old FWC's ??
But the only place I have seen it on the FWC's would be inside the front channel of the camper frame.
There should be a serial number written on the aluminum frame of the camper under the carpet that is at the very front of the cab-over bed area (inside – cabover bed area – behind bed cushion).
If you pop the camper roof up and pull down / pull out the cab-over bed cushion, usually in the front portion of the camper frame (Aluminum C Chanel) there is a strip of carpet tucked in there (inside / front nose of camper).
If you peel the carpet back, there is usually a serial number written in black pen. It will usually be in the driver's side / front corner written on the frame.
(SEE SAMPLE PICTURES ATTACHED)
If there is not a serial number ther, I suppose you could write a number and make a serial number for it ? Take the "just get it done" approach if you really want to get the camper registered.
Back in the days our serial numbers would be something like ... 12537-G
Hope this helps.
Happy Camping !
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