What makes a Custom Cab?

[55reasons]

I have had some time to review and search threads and I have to assume that my question is so stupid, nobody else has had to ask it.

Being used to working on VW's, I was surprised that the VIN doesn't decode the trim level of the truck.

Aside from having a strange issue with the VIN on this 64 I just brought home, (the 6th Character is a "H" which according to all the charts was not a valid character in that spot), how can you tell if a truck should have the custom cab trim or not?


What makes a "Custom Cab" a "Custom Cab"?

...so far the only differences that I can tell is chrome trim, etc.

If that's the case, what's included in that package?

What's a good reference to refer to for things like this?

Sorry, in advance, for the newb question.