If you are questioning the make year, the serial number tells the tale. On a '76 model year it is located on a metal plate on the glovebox door, a laminate on the driver's side door striker post (which should be intact on a original paint vehicle), and on top of the frame by the passenger side exhaust manifold near the wheel well. All three should match. I would ask for close ups of these three to verify before driving 600 miles.
Its something like U15GLxxxxxx where 'xxxxxx' is a 5 digit serial number preceeded by a letter.
'76 models years were built from August 1975 through August 1976.
1975 calendar years (Aug-Dec 75) range approx A00000 to B24999
1976 calendar years (Jan - Aug 76)range approx B25000 to D24999