Despite what that link says the 787 and 777 are not common FAA type ratings, neither is the A330 and A350 a common FAA type rating. In Europe and many other places the 777 and 787 are common type ratings.
Interesting. The original B787 FSB report states "the B-777 and B-787 are assigned a common pilot type rating"; however, the Rev 7 states "the B-787 and the B-777 are separate type ratings that have been determined to have commonality". What changed along the way?
Original:
https://fsims.faa.gov/wdocs/fsb/b-787_fsb.pdf
Rev 7:
https://fsims.faa.gov/wdocs/fsb/b787_rev_7.pdf