I was looking at the rear quarters to get an idea of when it was built, but I see no rear side reflectors which helps. There were a few minor changes around 2-26-68 which included the type of rear reflector's design and elimination of the hood turn signals (they became an option). Looks like the quarter panel chrome ornamental piece and the reflectors were eliminated on your car during restoration, which many owners like to delete the chrome ornament for a smooth appearance.
My current Mustang is also a '68 hardtop with a 289, but I also had restored another '68 (which had the 200 engine) which I sold about a year after I purchased my current Mustang because I really didn't have the garage space.
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I am located in Hyde Park just above Poughkeepsie.