Did a little research and it was produced for just three model years from 1973 to 1976. I'd actually never heard of the model before now.
I recognize Otto Perry's work anywhere! Love that as-delivered FT scheme and original numbers! Simply 'Grande!
They did a pretty good weathering job too... The correct, non-hilarious spelling is Morón (with the accent on the second "o"). There are towns so named in Cuba, Argentina, Spain, Venezuela and everywhere else where "se habla español". There's even a Morón Air Base in Spain! The actual English translation is hummock. So everywhere you go, expect to find a Morón.
I'll go out on a limb and speculate that the folks who altered the Monon boxcar weren't intending to make reference to a foreign city. Curious, though, that the Central Moron cane car lacks the accent over the second "o".