According to Dan Hagedorn in his book about Mustangs in Latin American Air Forces, N6165U was previously numbered GN 96 in the Fuerza Aerea de la Guardia Nacional de Nicaragua. It was sold to Maco Sales Financial Corp. of Illinois on September 2, 1963.
I knew this airplane (44-84634) back when Tom Kuchinsky from Wisconsin had it. That would have been in the later '60s. I remember holding short of the north runway in Milwaukee in a Boeing 720, while Tom came by for landing in this airplane (quite different paint). Quite a while later(late 70s probably), Max Ramsay from Kansas had it.
P-51D, N6165U was owned and flown by Tom Kuchinski of Milwaukee. The airplane was based at Timmerman Field in Milwaukee. My father also owned a P-51D, painted in the markings of "The Flying Undertaker", N5471V, based in Waukesha, Wisconsin. My father and Tom often flew to air shows in the midwest together, along with Paul Poberezney in EAA's P-64. Tom Kuchinski and his P-51 were lost in a high speed stall/spin accident in Harlingen, Texas. I'm not sure what year, 71, 72 or 73.