The only thing that says '74 to me is the non-drilled front rotor.
The signals look like the black plastic ones. Why would someone down-grade (in my opinion) from the '74 aluminum ones?
I think it looks pretty cool, and for $1600, I'd buy it if I didn't already have 4 BMW's. Well, maybe I'd still buy it...
Since the paint's definitely not original, I'd be tempted to give it an "S" paint job with the money saved on the asking price (assuming it needs nothing else).