Help with Decoding my VIN; 66 Chev fleetside

[Steve Schmidt]

Steve here,
I would like you input please. I have been researching my VIN and I would like confirmation/additional assistance. My truck is a 1966 Chev PK with a VIN:
C1446S162433. Inside the cab on the driver's side left kick panel their is plate that is barely readable, what I can make out is 5000, STD, and 525AA.

I found a link that has assisted my decoding:

http://www.americanclassic.com/paint.htm?p1=vin

I now know that this truck was manufactured in St. Louis, MO and was number 162433 produced.

I am trying to find out other specifics. I was told it came with a 6 cylinder and three speed transmission. Any information would be greatly appreciated. Another question is where on the rear axle is the code that indicates rear axle gearing? Thanks all. I attached some pics, hope it worked!