In one of the 1st grouping of pictures, there is a picture of the frame and it looks to me that the fuel select switch, between the front and rear tanks is just hanging out, with no knob on it.... Looks like it has the two fuel tanks, charcol canister lines are present on the passenger frame.
If you have headers, they may have to have a Air Resources Board exemption number... As this part is ok, cause it will do the same job as the stock cast iron manifold. But I doubt it, since the cast iron manifold has provisions for the pre heat stove that is used to warm the air that goes into the air cleaner snorkle. It also has a preheat tube that heats the air that goes into the choke.
The seller/owner is completely responcible for the smog to transfer title to you... unles you wave it. Don't!
17k+ stills seems high, I would expect to see everything in its place and smog compliant.
Also if it is a 77, it is missing the front sway bar...