Driver fender is a hot mess...

I would replace it with something correct and nice.
By the time you monkey with modifying a 67 or 68 fender to have the correct marker, you're almost back to square one.

Good luck finding a good used one. They are usually overpriced and still need some work. By the time you fix it, you're almost to the cost of a new one.

A 69 swinger is a valuable car these days, having a nice one is a privilege, it ain't going to be that nice with scars of old body work from people being cheap decades ago.
69 Dart Fender LH 200 2069 L

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