lolwut
If the order of the last two letters mattered, you would be able to refer to 6 different stickers on the same corner piece!

O :O !!!)
For specifying a sticker on a piece, people use the first letter of the name to say which face they are talking about.
UFL (or ULF) = U face sticker
FUL (or FLU) = F face sticker
LFU (or LUF) = L face sticker