Do you know that paint job to be original 50 year old from the factory?
Its at least seen a touch up or two
Oh you are correct I didn't thought that there could be a difference in painting between big and small block.
You may not realize that the engines were built at different plants by different workers with different directions often. Plus just different engines with different parts like Bob mentioned.
Not much in the way of unrestored S code 68's since allot of them were modified and used heavily. Though the parts that were installed prior to paint aren't that hard to figure out. Pay attention to things like the fading on the engine plate, if the car is a manual or automatic transmission (makes a difference in how they were painted) and what Thermactor parts were installed before and after paint