Just returned from a train buying vacation to Texas. Here is an unusual American Flyer 1218 engine in green with red lettering. Have never seen any of these engines with red lettering, other than the orange 1218 engines.
The red lettering on green background does not seem to have enough contrast to be readable, so possibly that is why this does not appear to be a common variation. The more typical variation is green with yellow or gold lettering.
Here are some of the more typical variations with gold and yellow lettering.