Recently, I read that Gene Roddenberry purposefully placed the name Noonien into his Star Trek works as he was trying to contact an old friend of his, Kim Noonien Singh. Khan Noonien Singh and Doctor Noonien Soong were named so because of this. Did Singh ever contact Roddenberry because of Star Trek. I am aware that this may seem off-topic, so feel free to mark it as such, administrators.
According to this story - no, his attempts (both with Khan and Soong) did not attract the intended attention:
Back in the day, when Roddenberry was flying his combat missions with the 394th Bomber Squadron, 5th Bomber Group, 13th Air Force in a B-17 Flying Fortress, he met a Chinese pilot who became his friend. After the war, he lost contact with the man, named Kim Noonien Singh.
It is worth noting that according to Marc Cushman's "These Are the Voyages: Season One" - it was indeed Roddenberry who changed the name of the character to Khan Noonien Singh from the original name(s) written by Gene Coon. There is, however, no detail in Cushman's work as to the source of the name.
Roddenberry is reported to have named the character of Khan Noonien Singh after his old war buddy hoping that the original would notice and try to contact him again.
Sadly, the character of Khan failed to gain the attention of Roddenberry’s former comrade.
Roddenberry tried again to hail down the Chinese pilot he once knew in the much later series Star Trek: The Next Generation, which began in 1987...this time, Roddenberry had the “father” of Data (the ship’s android crew member) named Dr. Noonien Soong. Once again, Roddenberry’s noble pre-Facebook and Google attempts to find his long-lost friend failed.
Additionally, there is another Singh in TOS - that of Lt. Singh in "The Changeling"
Looks like, at least one of the original sources for this story is this book