I know you asked Dwight but I think its a 1968 Norton 750 Commando Fastback. Very desirable. Looks like its in good condition too. Don't know about all original though as I am pretty sure they had drum brakes on the front and I spy a single disc there. Also bar end mirrors is not original. The front mudguard supports are not there and the rear shocks are minus the chrome sleeves.
Probally all done intentionally and in good taste, with the brakes being disc would definetely be an improvement. I would buy it at a reasonable price for sure.
Oops looks like I am incorrect and Dwight beat me to it.
