Tangent:
The year numbering in FF7, even without the odd use of Greek letters, strikes me as one of those weird peripheral aspects of canon that almost feel like it doesn't belong because the characters themselves almost never mention a year by its number. The date system is there in the background and sometimes announced on the screen, but the actual dialogue sticks to speaking in relative time (X years/months/days ago).
The primary exception to this is
Before Crisis - Special Episode Legend where both the specific years and the Greek letters are used by the in-game individuals. It doesn't just happen once, but a whopping ten times!
Legend: …
Do you remember what happened back in [ μ ] - εγλ 1997?
Makes you wonder how this line would have been read out in an audio version. "Do you remember what happened in mu dash epsilon gamma lambda 1997?"
Or did he simply say "muegela 1997"?
The other exception, as far as mentioning a specific year number in script, is
Special Episode Reno when the titular character has to enter the year when mako was discovered.
Reno: I’m running out of time,
so here goes nothing.
Lesse, Mako was discovered…
Choice:
>1. 19590923
2. 19680109
3. 19760624
Somebody tell me if there are more cases like this. And no, I don't count the moment where Sephiroth binge reads in the manor because the year is only represented by an X.
Sephiroth
“X Year, X Month, X Day.
Jenova confirmed to be an Ancient…”