this is one of those good ones! The unit codes for the pieces and the build are 1981 & 1982
The 545A started production in 1984. Maybe they weren't selling well, and/or was awaiting pieces to finish production and it sat, be interested to hear others opinions
Putting in the serial number at the Ford /NH/Case parts site it's a 545A
545A - 3 CYL TRACTOR LOADER (01/84 - 11/88) C690156
DD411K
DD4 = 545A Industrial 1984-1988
1 = Diesel Engine
1 = No PTO
K = 6x4 manual reversing Transmission
The C690156 serial number is from the first half of the years production (July began with C691700)
The Unit Number 2F09B
2 = 1982
F = June
09th day
B = second shift