Going crazy with VIN and engine#'s

[chis]

I know you all have heard this thousands of times but i need help with these numbers. I am looking to buy a 84 911 factory wide body. The car has 85k miles and looks to be in very decent shape. They are asking $22k
The vin# is WPOAB0912ES2117 I ran it on Carfax and all is cool. I cannot figure out what the # 2 is in the ninth place. I also check all the option codes and it is indeed a facoty wide body.
Aside from the ninth digit in the vin it looks to be ok. But then i have the engine and gearbox numbers (930/021) (64E -onwards) which all seem to be cool as well but the gearbox is 915/70 which corresponds to the F series 1985 and not the E-series 1984.
Also the numbers run motor 930/021 -64e 915/40 - 74E what does the 74E on the end mean?
If anyone can help would really appreciate it. I have been trying very hard to do my homewaork on this car and have looked at a ton of cars. Trying to join the ranks of proad 911 owners. Thanks in advance

[BierHunter]

I just started researching numbers myself, so I'm not an expert, but I've found this site helpful.
VIN #'s

Also...

...corresponds to the F series 1985 and not the E-series 1984.

According to the page I linked to, the "E" in your VIN seems to show it as an '85 model.

Hopefully, there is someone else around with more knowledge and can help shed some light.