'76 was the first year of the windshield angle change.
It is possible they gave you doors for a '75 and older.
It is also possible that your rig had an earlier windshield swapped onto it.
Is the windshield angle too steep, overlapping the doors? This could indicate that you have earlier doors.
Is the windshield angle not sttep enough, not coming back to meet the doors? This could indicate that your windshield frame is an earlier version.
You may also simply be having problems with the cowl strip, if it is new and not settled, or old and compressed...
Can you provide pics of the misalignment?