I have a "project bike" I got and am almost done- now trying to accurately date and get right decal. Atypical S/N on head tube is J1035494 I'd think this was a 1971 except for the 7 numerals instead of 6. It is a 5 speed tandem, I was told it was a twinn, but I'm thinking deluxe twinn now. Will get pix on soo, as I also need to assure rear reflector I got with it is period correct. Thanks!