It's likely that you'll have to heat the plate in order to install a new bearing , much like installing a motor case bearing . I believe the bearing should be flush to the back side of the plate .
The drive pulley is flat on the sides . There is some space between the pulley side and the back side of the plate . That space is determined by the plate mount and the spacer ( #4330 ) for the forward case to plate bolt ( #3157 ).
I don't see a need for the washer / spacer ( #1260 ) other than to maybe insure that the plate bearing outer race could never come in contact with the drive pulley , but
Exactly why some had them , I really don't know for sure . The plate bearing has little to no side pressure . It seems to me that it's main purpose is supporting the flywheel and adding counter or resistive support for the drive belt .