Yes at times you will be lucky enough with EY scheduling to get a 787 which has a 3 class config on a route which is sold only as a 2-class (i.e. no F)

Easy way to tell is, if you are on regular 2-class 787 seats start at row 5 (there is no 1-4), vs the 3-class 787 the seats will be row 1, 2 skip 3/4 and then straight to row 5... if your flight has rows 1/2 available, and if you can snag the rows 1/2 you will have the F hard product.. service will be the same as J..