Early Mustangs, Falcons, Mustang 2 and the Thunderbird Turbo Coupe had the 4 1/4" bolt circle. I believe they were all 4 bolt. Funny thing, the 1950's Austin A40 also had the 4 bolt 4 1/4" boly pattern.
I'm not sure why you brought this up. There was no confusion regarding the number of wheel studs on the axle in question. 4-lug wheels have no bearing on this discussion, nor any involving the RWD Chrysler-built cars of this era. Why bother?