"general way to differentiate whether you are looking at an old motor or a newer version motor"
Yes but in the case of picture #1 there is a 59-62 valve cover on an engine that has the older Carter W1 carburetor and also the horn mounted to the intake manifold.
This tells me that the exact year of engine manufacture is suspect. The engine could have had a dented valve cover and a previous owner swapped it out.
The engine serial number, block & head casting dates and numbers are better identifiers if you are seriously wanting to determine the year(s).
