Seam sealer & general floor appearance (spot welds, metal) look about right, though it appears the plugs are missing.
Looks like overspray on the side marker retainers; nothing should be oversprayed in the trunk.
I can't clearly see if the fuel tank vent line is there, should be natural finish.
Inner faces of quarters should have a heavy coating of sound deadener, masked at side marker areas.
I don't have my '68 here to confirm, but IIRC there should be a few more (plugged) big drain holes closer to the rear body panel.
Look underneath, at the quarter drops, for a drain hole in each one, those also get vinyl plugs with a drain contour.
Rear wiring harness should have a woven fabric sheath over the length of the wire bundle. Those did decompose over time.
In one photo it looks like an added ground wire. Could be a problem.
Get in the trunk, look (or feel) below rear window & up the C-pillars for rust, welds low on the pillars, "bondo worms".
If you see a seam running along a quarter from tail lamps forward (where panel goes from top to side), quarter has been partially replaced.
Also look at the underside of the trunk lid especially at the rear, and give it a shake up/down listening for rust particles.
See if there's at least a spare wheel, if not a wheel & tire. There's also some hold-down stuff for that.