early/late GMLAN messages will be dependent on platform....not year.

The C6 vette was one of the first vehicles with high speed GMLAN on the powertrain, but still used Class 2 for the body/interior....thats why they used the early GMLAN ID subset.

When GM went to the new electrical architecture that introduced GMLAN for the body/interior (which would include GMT-900 truck/SUV) and abandoned all Class 2, they switched to the "late" high speed GMLAN config and ID subset....they still use this same high speed ID subset today. ie a 2008 silverado, impala, express van will have mostly the same looking high speed GMLAN ID's and bus traffic as a current 2018 global-A vehicle. Obviously a current vehicle will have many more modules so there will be a lot more additional ID's, but the core high speed ID's are still the same.

It was only the very first high-speed powertrain-only GMLAN-equipped vehicles that used early GMLAN where no ID's/messages are shared. C6 vette, some 2004ish Malibu's and Saturns, cadillac XLR....idk maybe a select few others.