There were a smattering of foreign-born players when the NBA started in 1947. But in terms of players not from that initial season, there were only 3 foreign-born players who pre-dated John Brown that appeared in NBA games.
Chris Harris born in the United Kingdom who started in 1956
Tom Meschery born in China who started in 1962.
Al Cueto born in Cuba who started in 1970.
Then John Brown came along in 1974. So as a little trivia John Brown could be considered one of the pioneers of the foreign-born NBA players. Germany has had 14 total players born there that have gone on to the NBA, tied with Serbia as with the most of any country.