69 could come with optional tinted (band) front windshield and clear side glass, or tinted (band) front windshield and tinted side glass.
Like Bob says, the tinted rear windshield was standard.
Don't know when that started, I had a 66 Mustang fastback ages ago, and can't remember if the rear was tinted or not.
Elsewhere in the automotive world, the 66 Charger did not have a tinted rear windshield as standard, but 67 did.