In 1968 you had the choice of three options for glass.
1. No tinted glass.
2. Tinted windshield only.
3. Full tinted glass.
So there is no possibility of a windshield being clear glass with no mask on top with the other glass being tinted. More than likely the windshield has been replaced. A Marti Report will tell you what direction to proceed.
Back to this.
I have a full set, minus vents, of original 68 Coupe windows. All dated close.
However, Royce indicated 3 options but I'm not sure what those two tint options meant.
What did tinted windshield only mean? From previous posts I was told this meant tint at the top or 'banded.' I think the term used for this was 'SUN VISOR', as noted in the windshield.
But the windshield I have also has the term 'SUN-X.' I know what the Sun-x means, but I was told windshields were not tinted.
There is no doubt the whole window is tinted and matches the side.
In the pics below (left to right) are a clear window, Sun-x side window and the Sun-x/Sun Visor original Carlite Windshield.
Next is the front Carlite logo.