older trucks (1983 to 1994)
For '97 the layout was whey they call DSO - #24 Special Order Code. RC #23 is
Sales Region Code that's the one you're talking about. They are 2 different things. I don't see RC on his in the same place as mine, but it's a little hard to read some of it (need better sticker picture).
Nice to know the Sales Region Code but you have to look them up for the year under discussion as I believe there were changes over time. It doesn't tell you where it was sold though and some Regions are pretty big.
For my XLT I know where it was made, what region, and I also know where it was sold, about 25 miles from here. From the Carfax I found that it was originally registered in this town and although there were 2 owners (about 19 years and 5 years they held it), it still was always registered here. So that was kind of cool to know even though it's of limited actual value.
And of course the VIN tells you the plant where it was made.
To me the more info you have the better even though a lot of it doesn't help at all, but it might, when you go fix it.
Anyway yeah, totally, that's a diff gen you're talking about so it wouldn't be unexpected to have all kinds of different things; so we know that decode process is gen-dependent and maybe sometimes year dependent.