I am no expert on the subject or Steinbeck I can only say that as someone who is playing the part of Whit in the play "Of Mice and Men" I have asked the same question and since nobody else has an answer I looked around and believe that I have an idea of what is meant by the phrase Manila Goo-Goos. Based on the context of the term I believe that the short answer is that is a derogatory term of the 1930's used to describe someone who is from the Philippines. During the depression there was a population of Filipinos' working in California and there was an effort to deport these immigrants back to Manila so that the jobs would open up for out of work Americans.
There is no reference to "manila goo goo" in John Steinbeck's novel "Of Mice and Men." It is possible that this may be a misinterpretation or a reference to something else outside of the novel.
Ranch
The play 'Of Mice and Men' was written by John Steinbeck in 1937.
"Of Mice and Men" by John Steinbeck was first published in 1937.
'Of Mice and Men' was written by John Steinbeck and published in 1937.
The Christmas gift in "Of Mice and Men" was a set of playing cards.
Of Mice And Men was published in New York City in 1937.
"Of Mice and Men", written by John Steinbeck, was first published in 1937.
2 right now Of mice & men The Flood
Slim the jerk-line Skinner in of mice and men.
Conan - 2010 Of Mice and Men and Their Mutant Offspring Mice-Men 3-152 was released on: USA: 21 October 2013
In Of Mice and Men, it is stated that Carlson owns a Luger.
mice and men takes place in san francisco California