That's a nice old Bonny Larry, with a single carb (probably Tiger) set-up, hence your mate's confusion. The T120R serial number is the key, that identifies it as a US export 650 Bonneville.
They're a lovely bike mate, light, fast(ish) and great handlers. (quite different from the Golf Cart) I'd replace the seat with a double seat as chicks dig Triumphs, but I'd leave the bars and forks as is, as a "homage" to days gone by. Dust off your "Captain America" helmet, and enjoy. Great find! Cheers, Terry.