Well vehicles do have standard markings. But they where not
done like it should be by the GIs.
On the hood or bonnet is has the regristrationnumbers (not serial) and USA, all late trucks or Jeeps probaply around 1943 where radiosurpressed
and therefore the got a S on the hood.
For invasions jeeps and trucks got measurment sizes and weight painted at some places, where space was available.
In the cab they painted the tirepressure amount sometimes or maximum
speed.
On the hood they painted for preparation of the winter, antifreeze, winterezed or prestone whene the vehicles was prepared for the winterseason.
And you have the nicknames, sometimes called after the company or batalion, whatever it could be anything.
Corné