There is a significant flaw in this entire line of thought.  The P-51 is still being used to a greater extent today by air show pilots than it EVER was by the Dominican Republic.  Therefore, it's 1957 or present.  If you argue against using 1957, then you must also argue against using 1984 unless, as I said, it's not an absolute date we're looking for. The Confederate Air Force operates P-51's on a regular basis as do several other private organizations and individuals. Therefore, there is going to be an astrics on ANY date we put in there, it might as well be a significant date. Therefore, using your arbitrary logic, I'm going to put "present" on there and see if that flies.