Change date for the FJ60 steering box is 4/85. The 60 frame was modified to accept the 70 series box after that date.
FYI, this probably applies to the BJ series as well. I had no problem swapping my steering box between my post '85 BJ and the HJ61 frame I'm using (year unknown). The holes were already milled into the JDM frame, just needed to add sleeves. Box fit perfectly, I measured the steering box bolt pattern in my '62 and it was the same.