It looks like it was attached and then painted with the rest of the engine.  Nothing special.  That being said, John Schwiebert knows a lot more about this than I do, so I would lean toward his unpainted notion.  The only thing I always try to think about is manufacturing....how would they have built the tractor and in what sequence.  Maybe they put the plate on after the engine was built and painted and then put the data plate on....makes sense, but so does the other sequence.  I ramble...

Regards, Patrick