From the beginning of the 787 design Boeing had a short course for differences between the 777 and 787. I believe I heard the min Boeing course is 3 days and I'm not sure how many sims. Boeing was trying to duplicate the 767/757 abilities for pilot staffing.

There never was a Boeing short differences course for 747, 777.

For regulatory purposes the airlines can equal or exceed the manufacturer's approved training and in UAL/CAL's case they exceed the min Boeing differences course.