Tom-
The stock gear ratios for G50/50 are:
1st 41:13-3.15
2nd 34:19-1.79
3rd 33:26-1.27
4th 29:30-0.97
5th 31:41-0.76
The serial number looks correct however. Looks like possibly the gears for 3rd-5th have been swapped out for NA gears, which is a popular thing to do if you have PORSCHE POWER.
G50/50 or G50/52 with tall 1st and stock 2nd-5th works pretty darn well for most all around V8 applications. With 2.62 1st the gear are very much like early 90's Vette 1st-5th.
The stock side plate is paper thin and won't do for V8 POWER. Billet side plate is the only way to go if you want to keep that electric speedo.
LSD standard optional-40% and it's not worth keeping in my opinion. One single friction disc is just not enough.
Hopefully it wasn't run hard and put away wet!
Roger Brown
California Motorsports - Porsche transaxles, gears, differentials, parts and service
The Porsche Transaxle Specialists