The 6.2 made its appearance in the C/K trucks in the 1982 model year.
The red block was only 82.
The 83 and later was black....
The 82/83 had the coarse threaded injectors/heads

The 82 heads had larger valves and the heads were more prone to cracking......

Also the 82 heads had an extra water passage and those were prone to leaking at the head gasket....

A am pretty sure the Early "Red" blocks were 660 castings.....

The cast rockers were dropped in the 84 model year....