This is from another thread courtesy of fellow Tugger Michael Coley
Looking on RCI, here are the unit numbers for BLT:
2AF/2AS/2AU (F/S/U is the check-in day of the week)
2B1/2B2/2B3
2BF/2BS/2BU (F/S/U is the check-in day of the week)
2M1/2M2/2M3
2MF/2MS/2MU (F/S/U is the check-in day of the week)
2SF/2SS/2SU (F/S/U is the check-in day of the week)
The first character (2) is the unit size (2 Bedroom)
The second character (A/B/M/S) is the view. I think B is Bay/Lake View, M is Magic Kingdom View and S is Standard View. I'm not sure what A stands for.
The third character (F/S/U and 1/2/3) is the check-in day of the week (Friday, Saturday and Sunday). I'm not sure why they have two sets for that.
Nothing in the unit code tells the number of bathrooms, though. Those should be the same for all 2BR units.