i'd say it's a very straight looking Mk1 Series 2 as they are unofficially known. Series 1 has the round rear light and a couple of other small differences.
many Mk2s were converted to Mk1s before parts got scarce, but the giveaway is usually flush filler tank and wider forks with air assistance and different mudguard to fit. the ridged kick plates on the footrest hanger look like Mk2 bits, but it was probably just a late build.
it's got a later vented plastic alternator cover fitted in an effort to extend the alternator life. correct ali ones are pretty rare now. i sold one years ago for nearly £100!
the fact that it's a US spec is obvious from the nasty extended headlight rim, necessary to house the US mandated sealed beam unit. indicators are missing. possibly because they probably had the huge side reflectors built in.